Audition - I watched with my flat mate and gf of that time. They both got very After the the movie ended, she turned to me and said if you tell me you enjoyed that film then I am breaking up with you.
Gummo - love it or hate it... enough said
Best in show - i suppose no reason but I love it and lent it to friends that could not stand it. I think they just take it too personally as they cook dinner for their dog every night and so maybe they thought I was making fun of them when I lent them the movie
No Country for Old Men - some people seem to hate the ending so much