Really don't understand the hate for this movie

I feel the same. It had great moments. It's a decent comedy/drama. However, I felt some of the characters were wasted, sort of like his brother played by Peter Dinklage.

"By what right does the wolf judge the lion" - Jaime Lannister

I feel like this movie couldn't decide what it wanted to be. Like it wanted to be funny and serious at the same time. IMHO it couldn't quite pull that off.

Plus I found the plot to be a little unrealistic (it's hard to explain, but there are some genres where I can suspend disbelief, but this genre isn't one of them)

I don't get the hate either. There's a lot worse. Decent 7/10.

It's not a very good movie, what's so hard to understand?

The plot is dumb and contrived. The script is weak and the acting is not that great.

Here, for example, the angriest man in Brooklyn has a car accident with a taxi cab driver, who just happens to drive an SUV, instead of a sedan, like most cabs.
Then, later in the movie he accidentally gets in the same cab??

Really?? There has to be dozens of taxi cab drivers in Brooklyn.

and how about when he jumps off the Brooklyn Bridge and the extent of his damage seems to be a sprained ankle.

This movies sucks and it actually deserves the criticism that it gets.

Bob, re the taxi, never heard of irony? I'm guessing not. The mad cap nature of the film along with it's unlikeliness was intended.

Guess some expected it to be something it wasn't.