If it's obvious that you're joking which the study says is made clear with visual facial and vocal cues , pointing out a quirk in someone shows that you still like them for who they really are.
Why Can't I Stop Teasing My Crush?
If someone truly intimidates you, you'd never dare poking even the gentlest of fun at them because you have no idea how they'd react.
If you're generally not a super-serious person to begin with, then the idea of being blunt about your intense feelings for your crush can especially make you revert to your jokiest ways.
It's completely normal to be juuuuust a little mean to someone you want to date. They might be able to take a joke about their accent, but not about their.