Like, if you give a poor person some money, they'd be likely to spend it or give it to someone else.

That's not because they're crazy or stupid. It's because

1) Their standard of living is so low that blowing money on something seemingly ridiculous like new sneakers will give them satisfaction for a long, long time and may raise their social status among their peers.

2) They don't have substantial financial savings and you probably didn't give them enough to have some, so their best economic bet is to stay good with their frens and relatives or impress someone to make a good connection.

3) Their chance of getting more of that money is very low, so the relative risk of gambling it away looks more attractive.