This was the most enjoyable romantic comedy I've seen in a very long time. Let's find out why.
Many many romantic comedies are plagued by what I like to refer to as 27 Dresses Syndrome. This is when we are presented with a flawed female protagonist (not a problem in itself) who often has problems in the workplace (slightly more problematic), but who generally has no access to enjoyment (there's the problem). She then meets a man who is either significantly less flawed or not flawed at all. She can't have him right away, of course. He has to be: A. already in a relationship, B. uninterested, or C. generally unavailable. The obstacle is eventually overcome and the female protagonist's flaw is cured and her access to enjoyment is regained (because of the love stuff).
This should be an obviously problematic formula for feminist reasons (i.e. the movie is saying women need men to succeed, to enjoy, to survive at all), but, as always, I prefer the unintuitive Lacanian explanation.
What is happening in 27 Dresses Syndrome is not actually two people meeting and falling in love. The flawed protagonist is the only one of the pair who actually constitutes a person. As subjects within the Symbolic order (adult humans), our subjectivity is constitutively split and (except in a state of fantasy) we feel our lack, feel that something is missing. That something missing is objet petit a, or the object-cause of our desire (not something we can actually get, of course, but a fantasy object). In 27 Dresses Syndrome, the protagonist is lacking (because she can't enjoy her job or her life as the case may be) and the object-cause of her desire, that thing which she thinks will make her complete, is the man. In this scenario, the man is not a person, but a fantasy object (Lacan's matheme for this scenario is $<>a, split subject encountering the fantasy object). Thus what is presented as reality in the movie is not something that can ever actually happen.
Films like this are therefore by nature masturbatory (audiences who identify with the protagonist can enjoy them as long as they ignore that they're enjoying an object instead of a person). Perhaps more problematic is that they also offer an incredibly appealing and yet constitutively impossible fantasy scenario for impressionable audiences to identify with/look forward to.
But enough of negativity. Excelsior! (It's a line from the movie.) Let's turn this negative energy into something positive. One of the main reasons I liked Silver Linings Playbook (aside from the excellent acting from everyone involved—probably the best Jennifer Lawrence I've seen, but I missed out on Winter's Bone) is that it does not participate in this trend.
First of all, the film begins with Pat (Bradley Cooper), turning the female fantasy scenario initially into a male one. As any good protagonist, he definitely lacks a whole subjectivity: he struggles with "undiagnosed bipolar" disorder. Whether the film accurately represents bipolar disorder doesn't particularly interest me, so suffice it to say that Pat is lacking when the film begins. So far we have basically the same setup as 27 Dresses except from the male point of view (not a problem—my issue with the trend is where it goes, not where it starts).
The brilliance of Silver Linings with regard to this trend comes in the character of Tiffany (Jennifer Lawrence). By the end of the film she occupies the position which in 27 Dresses Syndrome is problematic for being unrealistic/inhuman. Tiffany, on the other hand, is just as messed up as Pat. While she doesn't have any scenes with a psychiatrist to give her problems a tidy definition, it's pretty clear that she's suffering from some sort of depression as a result of the death of her husband. In any case, she's constituted as lacking just as much as Pat is.
What plays out after their initial meeting is a give and take between the two trying to deal with each other's issues instead of the tired bait and chase of 27 Dresses Syndrome. The point is not that you have to wait for the perfect man to come along to fix your broken life, but instead that everyone has issues (albeit perhaps less severe than Pat and Tiffany's) and the path to happiness isn't patience (well, isn't only patience), but temperance and fortitude. The point is not that your subjectivity is split and you just need the right person to fix it, but that everyone is lacking and love involves taking the other's lack in exchange for your own even though you don't want theirs and they don't want yours.