I try this when someone's attitude stinks, I mean really stinks. I buy them something saying, 'I thought about you when I was in the store'.
Dollar Tree works wonders, or I say 'I love you' or 'Don't you just love them?' or if you cooked something - offer them some.
this way you have not lost anything.
Then watch later how their spirit changes.
give it a shot and watch 'problem' people turn into loyal friends!!