A classic paper on giving and happiness:
[Spending Money on Others Promotes Happiness](https://sci-hub.se/10.1126/science.1150952)
Elizabeth W. Dunn, Lara B. Aknin, Michael I. Norton
Although much research has examined the effect of income on happiness, we suggest that how people spend their money may be at least as important as how much money they earn... [P]articipants who were randomly assigned to spend money on others experienced greater happiness than those assigned to spend money on themselves.