I have re-watched all the season finales about a trillion times and I have come to recognize a pattern. I think my theory is more applicable to the last 3 seasons - from Season 4 to Season 7, but I would love to hear your opinions.
(1) Season 1 - Marshall is getting ready to propose to Lily, which has Ted's panties all in a bunch that he is not at that stage yet. I think the fact that Marshall was about to get engaged pushed Ted to the deep-end in his search for Mrs. Ted Mosby. At this point, Ted and Barney both meet Robin. Throughout Season 1, the viewers see that Barney just knows the real Robin. He knows that Robin isn't going to show up to Ted's "parties", he knows Robin's mischievousness and how she enjoys the bets that he comes up with that may or may not potentially sabotage her job, he knows how Robin would love a game of laser tag (even though at this point I don't think her love for guns was addressed yet), he knows the exact words to say to make Robin feel special whether its giving up a sure thing with the Asian chick in "Zip Zip Zip" to spend time with her or its buying her a corsage in "Best Prom Ever". In the Season 1 finale, Ted finally drives Robin to the brink and causes her to say "yes" to dating him while Marshall and Lily break up. This is a clear sign that the whole Ted and Robin relationship was never meant to be because when they started being a couple, Marshall and Lily ( soul-mates ) stopped being one. It was like a sign from the universe that by creating something false, something true had to be destroyed.
(2) Season 2 - Ted is dating Robin and Marshall and Lily have broken up. Ted is so self-centered and happy because he is dating Robin, that he puts down Marshall's feelings. Ted actually goes so far as to tell Marshall that it is no wonder why Lily left him because he is acting so desperate and being a "loser" for moping. Ted, that's like the pot calling the kettle black! As long as Ted got what he wanted, he didn't care about what Marshall was going through. Interestingly, Barney was there for Marshall and knew in his heart that M/L are meant to be together. Despite dating his "dream girl", Ted doesn't know a thing about Robin. He doesn't know that she occasionally will smoke a cigarette, he resents her fascination with guns, etc. In the Season 2 finale, Ted and Robin broke up while M/L get married. Its interesting that the break up between Ted and Robin is first revealed to Barney. All throughout that episode, Barney imagines the worst possible scenarios - Robin marrying Ted, Robin pregnant with Ted's baby, etc however in the end it turns out to be exactly what the universe wanted. No longer was this couple (Ted and Robin) that was a mistake to begin with together, all is right with the world and to prove it, M/L as true soul-mates (besides B/R) get married and are ready to start a new life together.
(3) Season 3 - Robin is dating a guy she meets in Columbia, while Ted is moping around at his failed relationship. Robin genuinely cares for Ted however she is not devastated by the end of the relationship. She is actually relieved because in all honesty she never loved Ted and she hated having to live up to his ideal standards of what she should be like. Robin wants to adopt a completely carefree attitude, an attitude that she is mirroring from her current boyfriend, and Barney calls her out on it. He knows the true Robin, and that person that Robin is pretending to be isn't it. He tells Robin that she is perfect the way she is and she doesn't have to change for anybody. She breaks up with her boyfriend. Robin and Barney are two peas in a pod. When Barney is trying to figure out who is sabtoging his chances with random girls in "The Bracket", its Robin who wants to help him out and wants him to hit on her in order to catch the bimbo. Not only that, its Robin who guesses Barney's plays correctly. "Sandcastles in the Sand" was a momentous period for both Barney and Robin because they gave into their feelings without worrying about the consequences. It was this "mistake" that Robin tried unsuccessfully to deny happened. When she tells Ted about it, Robin actually says that she tried hard to pretend it didn't happen but she can't. In the Season 3 finale, Barney gets hit by a bus and he realizes how much he is in love with Robin. The love he has for Robin is the last thing he thought of. This was an amazing breakthrough because the universe basically showed Barney that he isn't the carefree playboy that he always thought he was, but rather that he could actually love someone more than life itself. The universe gave Barney a sign - Barney you are alive and you have to see that Robin is the most important thing in your life before its too late because life is too short and you don't want to waste it.
(4) Season 4 - Barney realizes he is in love with Robin. He tries to fight the feelings but all he wants to do is to be there for Robin - whether its preventing her from becoming deported back to Canada, laughing at her jokes, helping her realize that she doesn't have to succumb to something that is beneath her to save a job that she doesn't even like, etc. In the Season 4 finale, Robin finds out that Barney loves her. She says in the sarcastic tone that she uses when she wants to pretend something is a joke but it really is the truth that she and Barney will get married and she even repeats that to Barney in the hospital scene. "Let's get married..." and Barney reacts "Stop smothering me." I think Robin realizes that she is absolutely head over heels in love with Barney but the problem is that the minute she wants something serious, he "can't handle it." This sort of reminds me of Robin's reaction to when Patrice asked her why she was so down and offered her cookies, "God, Patrice stop smothering me." We all know the symbolism of Patrice in the B/R love story (please refer to the awesome post that discusses this for details). In the end, fortunately Barney and Robin follow their heart and ignore their heads and take the leap.
(5) Season 5 - Barney and Robin have a great relationship until the gang sort of derides their relationship and tells them how the two most emotionally dysfxnal people will never have a lasting relationship. What is interesting, is that throughout the beginning of the season, Robin cannot fully trust that Barney is happy being monogamous. Barney is no help in allaying her fears when he talks about going to strip clubs and even lies to her about it. Robin knows that she wants a serious relationship with Barney but she is afraid that he isn't built for commitment. The gang is successful in tearing apart Robin and Barney and Robin decides to take a break. It is really the only time where Robin actively refuses to date someone after she has broken up with her boyfriend. Her love for Barney was so strong that she didn't even want to think about other men after their relationship ended. The fact that Barney was sleeping with any chick he met probably was the catalyst that pushed Robin into considering dating Don. In "Twin Beds", even though Ted was as much fighting for Robin as Barney, the only person Robin actually was affected by was Barney. The whole conversation in the end of that episode was literally all about Barney and Robin, Ted just happened to be a witness. In the Season 5 finale, Barney is all for M/L getting pregnant because adding a baby is awesome but the idea of losing Robin is not something he can bear. Barney is slowly realizing that the life he thought he wanted (single playboy) doesn't make him happy, being with Robin does.
(6) Season 6 - Barney has major growth during this season with Robin's help of course. Barney meets his dad. He finds it hard to accept Jerome initially because Jerome is a family man and not a party animal or ladies man - something that the old Barney would find awesome. It is through his relationship with his father, that Barney realizes how much he wants to change. Barney wants to settle down and he found the person he wants to settle down with - Robin. The universe gave Barney another push in the right direction - having his father show up to his door and actively seek out a relationship with him. Barney tells Robin how she is awesome just the way she is and how he loves her for who she is in "Baby Talk". Both B/R realize what an awesome team they are when they pair up in "Natural History" or when they try to prevent Ted from getting back together with Zoey. What's interesting though is that in that cab scene it was Robin who had to tell Barney why she understood why Ted would get back together with an ex. It was because they (B&R) love each other that it would be worth it. In the Season 6 finale, Barney has changed. He is willing to let the love of his life win ("Subway Wars") to make her happy, he is willing to give up blowing up something to prove to Ted that he does deserve to be the architect for a major project ("Challenge Accepted") - it is seeing this change in Barney that Robin realizes how much she loves him.
(7) Season 7 - In the beginning its very clear that Robin is in love with Barney but she is not going to reveal her true feelings because she thinks he is happy with Nora. I'm not going to delve into the entire season as its something we have talked about throughout this year but what I did want to address was the Season 7 finale. In the finale, B/R have a brief talk about running away together. Robin is totally serious - she says in the sarcastic tone that she uses when she wants to pretend something is a joke but it really is the truth that she and Barney should escape to Canada. Barney replies that Canada sucks. Robin then tries to tell him that if Canada sucks that he sucks a quarter because he is 1/4 Canadian but Barney tells her that he is awesome and she knows it. Initially, I was confused as to why the writers would cheapen such a poignant moment with a joke but then I realized that it might very well explain the reasons for Robin's actions when she says that she is happy for him. Think about it - Robin is Canadian, Robin has always been proud of her Canadian heritage and when she suggested Canada she meant it. Barney just took her words at face value and thought she was joking so he adds that Canada sucks. Robin probably views that as Barney saying that she sucks or is a "mess" and he is awesome and that she will never be good for him. I mean we all know that Barney and Robin are perfect for each other but there is so much miscommunication and denial between the two regarding their true feelings for each other that they each feel that they are not worthy of the other person's love.
Sorry if I rehashed all the old seasons in this rambling post but I have been thinking about Season 7 finale since it aired and I am trying to make sense of it. The producers did say that they wanted to make HIMYM like an epic movie so I just wanted to see if I could find a connection between all the season finales. I think it makes sense. I hope I was able to convey my theory in a manner that is understandable but maybe the main gist of it got lost in translation from my mind to the computer.