* Towards the beginning of the film, Pat states that he had suffered with undiagnosed bipolar disorder for most of his life. Based on how he acts throughout the film, I'm seriously wondering how that is possible. He's bad in social situations, blunt to a fault, and apparently prone to freaking out over mundane things like a bad ending to a book. How exactly did this guy get to adulthood, get a wife, and get a job as a substitute teacher without someone pointing out that he is clearly a few cards short of a full deck?
** In order to be diagnosed as bipolar, a professional has to diagnose you. Given Pat's family's working class character, it's very realistic that they would avoid addressing the possibility of mental illness. Pat's personality is also marked by a lack of self-awareness. Even though he now knows that he has bipolar disorder, whenever he has difficulties with people, his first instinct still is to assume that other people are at fault.
* I'm sure it was explained in the book, but what was the significance of the mayo jar? Pat had it with him when he worked out when he lived at the mental hospital, then it was one of the few things he brought home, and then for the rest of the movie it sat in the kitchen. What use did it have?
* Did Tiffany actually give Nikki Pat's letter and if so what was her response when she received it, was it so negative that [[spoiler: Tiffany had to write a response herself, if so, why did Nikki end up showing up at the competition and if it was negative why was she so happy to see him. Also why was Pat so cozy with Nikki at the end if he knew that Tiffany wrote the letter and that it was she who he loved]]
** No Tiffany never gave Pat's letter to Nikki and Nikki turned up at the behest of Ronnie and Veronica, as Pat had stated that marriages are worth fighting for and thus they Ronnie was trying to help him out as well. Also I would hardly see what was cozy about the two at the end at all. He basically tells her something that we don't hear but is obviously in the vein of that he's found someone who loves him for him but he hopes that she'll be happy. All of these questions are explicitly answered within the film, so I'm not sure about the reasons for confusion.
*** Wait, do we know that Tiffany never gave Nikki the letter? I can't remember if it was said that she actually gave it to her or not.
**** It was inferred after Pat made the Double-or-Nothing bet and Pat Jr. went out and reread the note, this time noticing Tiffany's "reading the signs" phrase, at which time he twigged into the fact that it was not Nikki's words (please note, too...the letter was done on a word processor. Not a guaranteed tell, but a good bit of foreshadowing earlier on, all the same.) Then, when Pat gave her the last letter, where he tells her he knew, she came out to say something to the effect of "You let me lie to you all week?" So yeah, we know.
* Correct me if i'm missing something here, but if Tiffany was trying to help Pat get in touch with Nikki, then why did she get so upset upon finding out that Pat might get back with Nikki again? Sure, Tiffany really loved Pat, and if she did, i'm sure she would have let Pat do whatever he wanted to. Granted, Pat seemed to be on good terms with Nikki near the end of the film, even if he had kinda moved on from her, but why did that detract from how Tiffany felt?
** No she wasn't at all, and if you remember she pretty much falls in love with him when he helps her when all those guys are coming to her house to basically have sex with her. It's only after that that she offers to help him get in contact (lying) if he does the dance competition which she obviously hopes will help him love her. She never had any intention of actually giving his letters to Nikki. Also as Pat was wrong basically for wanting to get back with Nikki considering that she was cheating on him and all that (remember Pat Sr telling him that Tiffany actually loved him while he doubts that Nikki ever did).
* Am I missing something, or did the movie have a disturbingly morally screwed-up ending? [[spoiler:Tiffany lies to Pat and manipulates him at every turn, specifically taking advantage of his sickness and delusions time and time again to make him dance with her. By the end, she's even deliberately manipulating Pat Senior's (frankly downright ''dangerous'') OCD and gambling addictions to her own ends, too. And we're supposed to believe that's...romantic? It's all swept under the rug in the last two minutes, where Pat dismisses it all as her "having to do something crazy to break his own craziness." I'm sorry, Pat, but systematically abusing the mentally ill and risking your family's life savings and then some go ''far'' beyond the realm of "necessary evils."]]
** What you're missing, in my opinion, is that everyone in this movie is varying degrees of crazy. We don't see enough of Nikki and the History Teacher to pass judgement on them, but look at everyone else. Pat Sr. has serious OCD issues and a fixation on the Eagles that is clearly unhealthy, and that same fixation was passed onto Pat when it comes to Nikki. Pat Sr. also has anger issues. Pat's brother seems to have difficulty relating to people socially in the first scene we see him, when he's naming off Pat's faults. Tiffany had serious depression issues and becomes attached to Pat instantly. Pat's doctor, while mostly normal, still has some odd tendencies for a shrink. Pat's friends are also a little crazy, one being trapped in a suburban life that's suffocating him and the other having been in Baltimore with Pat. The only one who seems completely normal is Pat's Mother, and notice she's the voice of reason through most of the movie. Knowing this, is it hard to believe that the other character's didn't react adversely to Tiffany's manipulation? They all have issues as bad or worse, and I would be surprised if they even noticed it.
** The point of the ending is not that what Tiffany did was good in any way (although things did work out and Pat Sr. gets the money he needs for his restaurant because of Tiffany), but that Pat understood WHY she did it. Tiffany seems to suffer from a sort of inferiority complex where she feels the need to give people things or manipulate them, because she doesn't feel worthy of people's love or attention. She even explicitly states this in the movie. Pat understood that the reason that she manipulated him was BECAUSE she loved him and didn't want him to leave. Pat then gave her exactly what she needed: even when her manipulations were discovered and Pat had a perfectly good reason to leave her, he instead stayed. The ending implies that Tiffany is doing much better; it's probably because, for the first time since her husband's death, she's convinced that she is worthy of someone's love.
** "Pat Sr. has serious OCD issues and a fixation on the Eagles that is clearly unhealthy"? Seriously, meet some sports fans. He's superstitious and given his livelihood depends largely upon the Eagles, his fixation is pretty reasonable. But seriously, sports fans are by and large the most superstitious people you'll ever meet. Pat Sr's behavior in that regard is just par for course.
** I had similar thoughts when I realized that Tiffany [[spoiler: faked the letter]], but I dismissed them pretty quickly. Contrary to what the OP thinks, she did ''not'' do it specifically to make Pat dance with her, but because she had realized at some point that she loves him. Does that make what she did right? No, it doesn't. But Pat forgave her because he finally realized what pretty much everyone else already knew, that his relationship with Nikki was over and that he needed to move on. Pat's friends and family presumably never made an issue out of it because of both that, and because they saw that being with Tiffany was making him a happier, healthier person.
** Tiffany didn't manipulate Pat Sr. She gave him completely accurate information about Philadelphia's victories.
* For someone obsessed with details in superstition, shouldn't Pat Sr. have dismissed Tiffany's "Excelsior" theory, given that the Giants are actually from New Jersey?
* Is there any reason to believe that Pat and Tiffany are anything but each other's rebound? There's no build-up for any ''real'' romantic relationship, it's all "so today I decided I'm in love with you". In Tiffany's case it seems like he's the emotional rebound when the sexual rebounds didn't work and in Pat's case he just turns on a dime from obsessing over Nikki to deciding "eh, I'm in love with Tiffany now instead". Which can be an interesting story to tell, sure, but great romance?
** You have to realize that a lot of people have had very successful relationships that started as rebounds. However, in this case, the two of them slowly fell for each other in the matter of a couple of months. They met just before Halloween and by the time the dance competition came, it was already near Christmas. Had Pat decided to sleep with Tiffany from the get-go, this would have DEFINITELY been a rebound, but instead he took his time with her and they formed a healthy connection off of it.
* Is Pat Sr actually running a book, or is he just gambling? My understanding (I'm no expert) is that bookies normally work things so that they profit no matter who wins the game, by taking bets on both sides. Pat Sr's obsession with the Eagles winning seems to imply that he only profits if the Eagles win.
** I think the thing with the envelopes shows that he's taking other bets. I think he just places big bets on the Eagles with his normal bookie.