Recently I stumbled upon Jenna Marbles' funny (and semi-old) video parody of the topic and decided to discuss it on a serious level.
What can make you go "no" in a relationship? Mind you, we are talking about mild and "normal" stuff here, none of the "if he/she turns out to be a serial killer" type of thing.
Personally, for me it would be his attitude towards people that aren't that close and important to him.. for example towards a friend of a friend, or even staff at an establishment.
Treating them bad might be a good signal of what's a possible outcome in the future concerning his attitude towards me.
What about you?
To clarify:
Just ending it right there, on the spot.
And as many haven't understood the idea of my topic:
Thank you Bob Saget!