This usually never happens to me because I like a lot of types of games, but stay away from things I don't. For instance, I'm not too big on the horror so if I were to get one by accident somehow it'd probably be an insta-nope, tho I'd still give it a chance in the end.
Only game I'd say had an insta-nope moment for me was Real Steel for the 360. I had a lot of fun with the demo, then read online about how it was just an EXTREME cash grab. Haven't played it since.
What I see when someone types AC --> Armored Core What they usually mean --> Assassins Creed...GAHHHH