Dealing with guilt

What happens when you walk out of a mall loaded with purchases and an old lady walks upto you and begs for that one extra ten rupee note which would help her eat one square meal?
I had just walked into a mall that I had heard of and bought a few clothes when we were accosted by an old woman and I could not stand it, I feel really guilty when I see an older person beg, I remember my grandma and feel like I die a bit inside.
What kind of human being would chase their parents out of their houses? What kind of human would forget that these are people who have spent a large part of their lives making sure we can make our way through this world with our heads held high?
And when we give them a little money, the hurt gets worse when they fold their hands to you. I usually give any old person money, and fold my hands to them, which makes my companions laugh at me. Why? Because these old people are supposed to be "grateful" to us who give them that Rs 10.
I would rather that I could give them a life where they need not go through heart-wrenching days of having to stretch their palms to young people whose duty it is to look after them.
I feel guilty as hell when I see them and I still do not know how to deal with it.