Why am I becoming cynical?

I am, by nature, an easy-going fellow. I try not to get involved in situations that don't concern me and keep a positive outlook as much as humanly possible. Faith helps this. While my faith is God has grown astronomically over the past year or so, my faith in my fellow man has decreased significantly in only a small number of months. Thanks to the citizens I deal with on a daily basis, I would now greet the average Joe Schmoe you'd meet on the street with a little more apprehension. I'd be a little less trusting than I used to be. Maybe this is just a result of age and life-learned experience. Maybe it's because I'm afraid of being taken advantage of because debt has made me more aware and protective of "things." More than likely, it's because approximately 70% of the people I come into contact with on the job are liars, cheats, and con artists. Could that be it? I still believe people are inherently good, but an overwhelming proportion of them that I am forced into "community" with are not expressing it. I still try to rationalize that maybe some of these people are actually in need. Maybe there are extenuating circumstances that have forces them into a desperate situation where they would risk legal action against them for fraud to obtain a little money to help their family. It's hard to sort fact from fiction sometimes. The lines get blurred. I just hope what I'm doing is right and I can maintain some sense of trust and optimism that our world will get better...