how ethical is it to give money to people on the streets?

My whole life I've been asked for money by people on the streets. It has never ceased to upset me.

It's a very effective -and unnecessary- reminder of my country's reality. Not only does it make me sad, but it also puts me in a very uncomfortable position: weather I'm walking around or driving in my car, there's something sort of abusive about someone tapping on my shoulder or knocking on my car's window demanding for something I'm supposed to have and obliged to give. Beggars, weather they're young or old, male or female, always have this look; this look: not precisely a sad one, more like a blaming one. While it always makes me feel responsible somehow, it still delivers a clear message of full resignation.

I try to have coins near by, I always carry candy (for children) and in the mornings I usually have one or two extra bananas. But---is that better than nothing? when can it ever be enough?

Money- how much is enough? how much is too little?
Food- is that polite?
Candy- how can a piece of candy help children that should be in school but instead are forced to collect a certain amount of money by the end of the day?

There's this blind woman and her son (I suppose) that come to my window every single morning, and it is really getting me down. I feel so responsible I sometimes try to avoid the street where they usually are, just so that I don't have to be in that so very unfair position. Unfair for both parties, I guess. Whose fault is it? Should they stop asking, should I stop giving, should this go on, is this natural?

Beggars have existed ever since history can tell. That doesn't make it right. It certainly doesn't help me know how to act.

I feel so trapped in this very depressing human reality, frustateddddddddddddddd