Random acts of kindness

I stopped by the local Chinese food place yesterday for some rice and soup. My regular server was there, and she must have been able to see I was having a crummy day and she gave me a hug. Very early this morning I went to the grocery store. I asked one of the stockers if they had any boxes I could use for moving, and he said he would set them aside for me and asked my name to make sure they were saved.

I know this is based in part because of my ongoing issues with depression, as well as current situation, but I teared up when these total strangers were nice to me.

Why does other peoples kindness affect me so much? Am I not used to kindness? Do I not think I am deserving? Or is it just the surprise that there are just some really nice people out there?