I've seen so many movies that I don't keep track of spoilers anymore.. I make a conscious effort to keep my disbelief suspended so as to not miss out on the gems amidst the charcoal, so that a movie has to really suck before I have no choice but to tell myself I have better things to do, and walk out.
Those movies I forget quickly, unless they're bad enough to feature in MST3K.
But off the top of my head, Pierce Brosman cast in any role other than the snobbish scientist in Mars Attacks.