Actually, I loved 12 Monkeys!  But then, I'm a very strange man.  Just ask the kids.  They'll tell ya!  That movie is pretty highly rated by critics and it rated 87% on Rottentomatoes.com tomato meter.  But, that's why they have a lot of different kind of movies, because there are different people out there! (and man, I'm as different as they come!).  For me, the worst movie ever, and I'm talking the dregs of moviedom, was a little classic starring Chris Elliot called, Cabin Boy. the only good thing about it was a 2 minute cameo by David Letterman and I bet if you ask him,  of the two, the better experience was the time he hosted the Oscars.  Pretty much unwatchable.