The guy who comes and works in my garden once a week asked me for several weeks' pay in advance about 2 months ago. He wanted to buy a TV for his daughter. It made me feel uncomfortable and I said no.
A couple of weeks later he asked me for several weeks' pay to buy fertiliser and to assist his neighbours buy fertiliser in bulk in order to get a reduction. I was only too pleased to help and gave it to him straight away.
Why did I refuse one and accept the other? Who on earth am I to decide what he should and should not spend money on? Surely he knows what is best for him better than I do, so presumably I have reduced his utility (happiness) by saying no to his first choice but yes to his second.
Either I have been taken over by paternalism and feel I know what is better for people than they do (rather heroic of me) or else I am being nice to other people for me and not for them (otherwise put, I am being selfish).
Economic theory would suggest that this can be tested. If someone else is gave money to buy fertiliser, I would reduce the amount I advanced if my giving is selfless. If it is selfish, I would keep giving the same amount - after all, what does matter how much you give a good cause? - I don't really care about the cause per se anyway.
I want to plant some veggies in my own garden. Donations of seed or fertiliser gratefully accepted. Or perhaps you'd prefer to give me the equivalent amount in cash so I can buy a fancy BBQ I've been hankering after instead.