How do I stop thinking of this?

So I was here with my cousin at spedys pizza so he can get food and this guy walks in selling banana bread he had trouble speaking and walked with a limp he asked us if we wanted to buy some and we said no he asked everyone else they also said no then he walked out
I had cash even if I didn't want banana bread I feel like I should've gave him some cash idk but I feel pretty bad about it and I can't stop thinking about it