So you are on your third date, things are going well, but then your date confesses to hating something that you love! Their opposition to this thing is a definite deal breaker
For me it would be Indiana Jones (1 & 3)
@HEAVY METAL
I actually think the casino scene at the start is in the fine tradition of the pulps, it goes disastrously off the rails after that though.
Sci-fi in general, I have met people that will refuse to read/watch it.
Video Games
I don't need them to play any or like them, but I game a bit most days and I'm not going to sit there and listen to a lecture on how they're terrible.
Tabletop games get an honorable mention.
I've honestly never met a single person who played a tabletop game and didn't like it
@HEAVY METAL
I tend to avoid religious people as much as I can