Don't be a scumbag — take relationships more seriously.
Tips
usage
渣 literally means 'dregs/residue' — the worst leftover part. 渣男 specifically refers to men who cheat, lie, lead people on, or emotionally manipulate partners. The female equivalent is 渣女.
culture
Extremely common in Chinese dating discourse. 渣男语录 (scumbag quotes) like '你是个好人但我不配' (you're a good person but I don't deserve you) are widely mocked online.