overly bad story or graphics, character models with unrealistically large tits & cock, when the authors biases come through too heavy (usually racist themes)
I don't mind tattoos. On the right girl with the right personality, it absolutely fits. They can be trashy and make an otherwise good looking girl look bad.
The one exception is face tattoos - they never look good
I just don't understand how popular foot fetishes are, nothing against it and it's not a turn off for me (unlike some of the more extreme - scat, necrophilia, etc)