$5 haunting

Every night when I leave work I see an old man in the parking lot. I can't say just how old because this poor soul is pretty weathered. He drives a very old rusty truck and always wears the same thing. I think he shows up sometime around when the mall closes and stays till who knows when. A lot of the people I work with get creeped out by him but I don't. It actually breaks my heart to see him. Last week I saw him as usual but this time he was looking through the trash- which if I had to guess is probably what he does everyday.
This particualr night I walked past his truck and noticed he had left his window down. I immediately had the thought "You should give him the $5 you have in your wallet. Just leave it on the driver's seat". But immediately as the thought came I also thought, "but what if someone sees me? what if they think i'm doing something mean? what if someone comes and takes it after I leave? what if he sees me and resents it?" I had a million different thoughts that kept me from acting on the first and more charitable thought. which I have to admit I am ashamed of. I don't need that $5 and in fact will probably never spend it. That 5 dollar bill will probably haunt me until I die because in my mind, it belongs to the old man from the mall. I once again let my fear of what others might think outweight a kindness. And now every time I walk to my car or open my wallet I remember what I should have done and didn't. I can only hope that next time I get a prompting like that, I act on it and tell my selfish thoughts to stick it! And hopefully in the near future I will walk to my car alone and his window will be down and I can correct the situation.