I live in a close knit family. I regularly see my siblings and parents, and the most annoying person of all is my sister.

Not because of anything she does directly, but because she seems to have a different boyfriend every year, and he's always the exact same loser: long hair, beard, tattoos of occult symbols, no job and a criminal record.

Every year it's the same shit: she finds some new dude, they enter into a relationship, she goes silent for a few months, she weeps and moans about how he's such a good man in between kicking her ass, they break up, repeat.

Tired of it.

How to make someone seem unappealing to someone else?
Preferably the archetype. If I never had to deal with another failed Dave Grohl clone with a goatee, I'd be a happy man.