1. A great villain.
2. An interesting cast with unique personalities, perspectives and ideals.
3. Smart or otherwise competent characters. I hate idiot plots.
4. Cool fights (less important, but can be the icing on top of the cake).

A movie doesn’t need all four factors for me to enjoy it, but nearly every movie I’ve enjoyed nails at least one of them. Some examples in no particular order:

1. No Country For Old Men
2. The Matrix
3. The Dark Knight
4. 12 Angry Men
5. Puss In Boots: The Last Wish
6. Kung Fu Panda 1 and 2