A run-in with a homeless man

Unfortunately our town has had many layoffs and there seems to be a growing number of homeless. Or maybe I should say there is a growing number of people who will stand on a median or interstate exit with a sign requesting help. Tonight I return from getting diapers at Target and I am faced with this decision. You see I don't talk about it much on my blog but I do believe in God and I very strongly believe in Matt. 25:40 about "whatever you do unto the least of these you have done unto me." This verse hits me in the face when I see people with a sign requesting help. While I am certainly by no means rich financially I feel obligated to show that I am not just a reader of the Word so to speak, but also a do-er. I have also seen a car in front of me give someone money and then in turn see the "homeless" person in the store buying beer. Sometimes I say a prayer for them. This feels safer to me because it has no direct contact, other than the uncomfortable feeling that lasts as you try to figure out where to place your eyes for the duration of the red light. I have bought them food and brought it to them, but tonight was different. I'm not quite sure what to learn from it.
I am sitting at the light which of course is a long one and the man can barely keep his head up. I had just spent my money on dinner and did not have cash, but there was a water sitting on the passenger seat. His sign read "homeless, any help will do." The water had been in the car all day and alas it has been mighty hot here, quite possibly a preview of hell! I roll down my window and say "Sir, I have a water - it's hot but you are welcome to it." Evidently he did not hear the "It's hot" part because he comes over and grabs it and yells "It's hot!". Then he throws it in the bushes beside him. I just shook my head and thankfully the light turned green so I could drive away in dismay. I guess I'm back to just sitting in my car and praying until I get the bad taste out of my mouth from this one.