Hands down, the worst movie ever made is:
Plan 9 from Outer Space... but so bad it's fun to watch!
Movies I wish I had never seen:
Highlander 2... the first film was excellent and mystical, about immortals walking the earth, living many lives, etc... but when the second film started, they said, "oh, well... we're not actually IMMORTALS, we're ALIENS, and we've not been around 'since the dawn of time' but only 500 years." What a horrible waste.
DOOM... I like a good action flick just as well as the next guy, but this just didn't get there for me. When the Rock started contradicting himself in the span of 5 minutes, I couldn't take it. First he was yelling at everyone that NOTHING gets through the gate.. at all costs, we must protect the earth from this virus or whatever it is! Then, a moment later, he's saying, "Our job is to get this data and samples back to earth for study, at all costs!" If you're going to protect the earth, don't take the virus through the gate WITH you, Tard... Which is it going to be? Make up your mind, muscle-head.