I never give to beggars. Ever.
Until today. I stopped for gas on my way to work, and there was a guy standing under a tree near the gas pumps, (out of the way), playing a guitar and singing. He really had a beautiful voice, and was a skilled guitarist. He had a sign on his guitar case, saying he could use some $ for gas. He wasn't bugging anyone, and made my time at the pump more enjoyable. So I gave him a couple bucks in change. He gave a genuine "thank you", and kept singing. I'm good with it.

but professional bums, drunks, 16th Street gutter rats, etc, never get a thing from me. They already get plenty of the money I pay in taxes, and I'm not happy about it. I find that being mean and gruff (ok, just being myself) tends to shorten the amount of time I have to listen to them.