I really don't like being forced to wear certain colors for certain holidays, but when I was little, my mom always put us in the pastels for Easter, red and green for Christmas, etc. Usually if I have some family gathering to go to for a holiday, I just wear my go-to black blouse. It's simple, but dressy enough to wear somewhere elegant.
I'm Irish so St Patrick's day is green, and I have this super awesome ugly sweater/turtle neck combo that I love for Christmas sweater parties...Or embarrassing friends and family with out in public around the holidays :P
Yeah on St Patrick's I wear green so some random person does not decide to pinch me. Also sometimes I will wear a Christmas themed shirt for Christmas or something for 4th of July but usually I don't wear anything for holidays.