Anecdotal, but I know of one case where the beggar got angry about being given food (I think it was something like a grocery store deli sandwich, still wrapped and unopened) and ranted at my friend about thinking they know better than the recipient about what they need and how the giver must not trust beggars with money and so on. It's kind of funny in retrospect, but at the time it was disturbing and confrontational and (of course) extremely ungrateful, so there were definitely no warm fuzzies derived therefrom (more like a highly unpleasant fight-or-flight moment plus public embarrassment) and it really did feel like a waste of money. If your goal is warm fuzzies, or even just to convince yourself you're doing some good, triggering an experience like that is utterly counterproductive. I can't imagine it's a common thing, but so far as I know, my friend has never again tried giving food directly (as opposed to donating to a food drive).