Actually, it's Happy Birthday to me. Growing up in SoCal Cinco de Mayo was a huge celebration. For my birthday every year when I was small I would spend the night before with my sister and her husband and kids and in the morning LBB and his then-wife would come over and we'd all go to Olvera Street in Los Angeles. When I was little I really thought that the celebration was my birthday party.
I can remember bouncing down the stairs and announcing to everyone that I was ready to go to MY parade.
I now live in an area where Cinco de Mayo is not so celebrated and birthdays aren't nearly as much fun. Of course, some people (who have no clue just how close they are riding to the ragged edge of disaster) have suggested that it's because I'm an old woman and thus things are just not the same.
I prefer to attribute it to the lack of parades.