When I worked in telco, I worked downtown. There were plenty bums and panhandlers down there. Including a bunch from some type of half way house. I do not recall if it was for mental illness or substance abuse, but it was a few blocks over.
I did the same as you. At first flipped them some change, then had gotten annoyed and said no, and then I would just walk by and ignore them like I did not hear them. I simply found disengaging them and not even acknowledging them worked best for me. Otherwise I would feel bad.
I really feel bad for the bums, but at the same time I worked hard for my money and get annoyed being bothered for handouts on a daily basis. Going into the building, going out for lunch, going to and from my car.
