My dad (rest his soul) loved this movie. For him it all came down to one quote which, for years, he said was probably the most honest thing he's ever heard about life in a movie:

"People are always talking ya about truth. Everybody always knows what the truth is, like it was toilet paper or somethin', and they got a supply in the closet. But what you learn, as you get older, is there ain't no truth. All there is is bullsh**, pardon my vulgarity here. Layers of it. One layer of bullsh** on top of another. And what you do in life like when you get older is, you pick the layer of bullsh** that you prefer and that's your bullsh**, so to speak."

It was one of his most favorite quotes and he'd paraphrase it all the time. Honestly I can say why, it's funny and true and that really works. it also really explains the movie.

It's about redemption, people that you'd never would expect anything good out of are honestly capable doing some amazingly heroic things. People that you would expect to be honest are capable of the worst lies.

The comedy is about perceptions and expectations and reality and it manages to have a profoundly honest message hidden in the layers of bullsh** that it builds up around it.

And, most importantly, it entertains while it's doing it.