Same here, well, as long as it's not a green light.
The ones that are grieving and looking especially down, or in pain, are the ones that I go up to and give a few bills/change voluntarily. Those are the ones who are consistently grateful.
I'm just like that by default, for whatever reason. Whether it's this, tips left at tables or Starbucks, or some dude asking for change because he needs gas, I can't help it. I just say okay, and I only curse my empathy when they are rude about it. Homeless or not.
I do think karma is real. Though it may not seem like it sometimes, that's only because I see a mere glimpse of a random person's/stranger's life. I think we all get what we deserve, in general and minus real tragedies.
That's not to say people pay the price for not giving handouts, lol. Far from it. People have their reasons, and they could be reasonable or hard to disagree with. But I think people do feel joy in doing this, knowing that we did something to help someone. That may be the only compensation that we get.