Interesting. I know several people that have interacted with him and found him to be quite nice... though one buddy dealt with both him and Patty and said she was a raving b-tch the first two times, then settled down.
Its also quite possible that people feel he's not a nice guy at the gym because he's there to work out and not take selfies, Much the same way many pro athletes and movie starts would prefer to be left alone when they are eating dinner or with their families.
Back to the movie though, just saw it last week. I wasn't the biggest fan of the movie. Just really dark (yeah, I know, it was a dark time in his life), and a bit awkward. The people just weren't believable other than Faye, who ironically was not a real person in his life but was a conglomerate of several women in his life.