Why are people nicer to attractive people than to unattractive people?

Last night I had my glasses on, a big sweatshirt, and a “bad hair day” from rain and wind. I know I did not look my best but I did not care. I went to Macy’s in the mall and did some shopping. Most people acted like I was not there. Of course the cashier was nice, because they usually have to be.

Today, I did my hair, did not wear glasses, wore a nice fall jacket and I think I “cleaned up” pretty well. I looked about as good as I know I can look. I went to the same store, Macy’s at the mall, and I was greeted by people that worked, there, smiled at by men and women, some people made small talk about the merchandise.

I am obviously the same person I was last night. However, looking better as I did today got me nicer treatment then I received last night. Why do you think that is.