It depends on what the 'thing' is, and the situation, but

If you really don't enjoy it anymore, and it's no fun for you, then stop doing it ... there's no point forcing yourself to do something you don't want to do, you'll just make yourself unhappy.

If deep down you DO want to keep doing it, but you're just getting frustrated by this person ruining it, then keep on doing it.

Don't let someone stop you doing something you love. If they're delibaretly trying to ruin it for you just ignore them - they'll get bored eventually.

If they honestly don't realise they're ruining it for you, maybe have a word with them? "I know you mean well, but it just feels like work, it's not fun anymore" or something?

Good luck with whatever you decide