4. The guy who’s rude to waitstaff.
Okay, this is weirdly specific, but it’s perhaps the easiest barometer for measuring whether or not someone is an actual human trash fire. If he’s snippy with your server or getting fussy with the bartender, it doesn’t bode well for how critical and high-maintenance he’s going to be in the relationship.
5. The guy who lets you pay for everything.
Sure, it’s nice to take turns paying for things, especially if neither one of you is a Rockefeller. However, if occasionally going Dutch has quickly become you paying for pretty much everything, that’s a toxic dynamic. Even if you can afford to be the moneybags in the relationship, it’s not doing you any favors to establish that kind of power imbalance. What’s more, the situation could easily turn into him using you and taking you for granted.
6. The guy who cheated on someone to be with you.
There are certainly stories of happy relationships which began as affairs. Unfortunately, most of those are actually fiction, and the majority of relationships that begin with cheating also end with cheating. While it’s true that you can’t really help falling in love with someone, breaking up a relationship isn’t an auspicious beginning to a real-life romance. If someone was willing to cheat on their past significant other, then what’s to stop them from cheating on you?
If your paths happen to cross again when you’re both single, then mazel tov — but don’t stir sh*t in someone else’s relationship, because it will definitely come back to give you a karmic kick in the ass.