How Do You Feel When Something Unexpectedly Nice For You.?

When somebody does something Unexpectedly nice for me I thank them and maybe do something nice for them. When people do nice things for me I know they care for me or are a really true friend.  I like doing nice things for other people but sometimes I feel like people don't appreciate what I do for them and now days people don't even say thank you. I try to be very polite to people that I hardly know, But like I said people don't appreciate what others do for them. I let people know that I'm trying to be nice or something.