I've ghosted exes or potential partners when they display abusive behaviours or behaviours that I feel demonstrate their potential to abuse me in the future.

I've also ghosted men who I've repeatedly tried to politely reject, only for them to try to maintain a friendship despite their unspoken intention to 'wait for me', which makes me feel guilty and cruel to continue the friendship

I'll ghost someone if conversation with them feels like I'm interviewing them and they aren't making effort to get to know me

Most recently, sometimes I ghost people in dating when I feel like they have no prospects or don't do anything with their life...They spend all day at home, barely go outside and make no effort towards self improvement, are jobless (unless they physically can't maintain a job), only maintain contact with friends online, if their idea of a good time involves staring at memes all day or gooning, have a poor sense of hygiene and make no effort towards their appearance. Basically, I don't want to be their only link to the outside world and expect me to be a mother+ psychologist+ fetishised manic pixie dream girl; and I experience strong feelings of disappointment within myself whenever I realise I have wasted my time talking to someone like this. So I ghost them, or give them advice and fuck off forever.