Well, I am not a callous SOB and do believe strongly in Karma so I try not to be cruel to homeless people. There are homeless people who are clearly mentally ill that just breaks my heart. The drunks and addicts I just stand clear of.
When it is freezing out my first thoughts are to thank God for the warm, safe roof over my children's head, and then I think about the children who aren't so fortunate. It grounds you.