There's a few individuals who seem genuinely kind and appreciative, and I try to do what I can for them (a sandwich, or a few bucks if I don't have the time). Others are clearly just a blackhole that you could pour an indefinite amount of money into. I realizing throwing people a few bucks won't make a difference, but at least it shows some recognition of them as a person.
I don't give money to crust punks/train hopper kids. Those people are awful.