Natural Born Killers gets my vote. Followed along with a chick to see it, thinking I'd get lucky afterwards. Talk about a mood killer.
Offshoot:
Movies that lubed them up.
Over a period of about a year or so, I took six or eight different girls to see either Officer and a Gentleman or Risky Business. It worked four times and almost worked two others. Those two reined up short of the goal.
In the few months before those two movies became staples, I tried taking one or two to Porky's. I laughed like hell, but they were not amused. I learned from this and changed tactics.