Don't constantly tear others down to build yourself up. Most people can see right through that, and it typically has the opposite effect.
When someone tells you they're uncomfortable with something, you should stop that behavior. It's not cute, fun, or flirting to continue purposely.
"It's fine to be confident, but if you need to put others down to feel that way, you're just insecure, and it's not cute," said one user.
Mistreating people you deem "beneath you" is a serious red flag. First, no one is "beneath you," regardless of what job either of you has. Second, everyone deserves to be treated with basic human dignity.
Some folks don't know how to let others participate in a conversation. They endlessly blather on about themselves, oblivious to others in the room.
All too many relationships are one-sided. Unfortunately, we can't always identify users immediately, but when we recognize it, it's a turn-off.
Empathy is one of the most important traits we can develop. It helps us understand others' perspectives and feel what they are going through.