As an adult, for me, birthdays have been "holidays" that I celebrate *with* friends, rather than the holiday that one's friends should always remember.

Ah, but celebrating a birthday with friends *is* a way to remember the birthday.

Yours is probably a better attitude to have. Which is partly why I've always felt a bit selfish for wishing more people would remember my birthday. It seemed wrong to be discontent, even if only a little, because of something so trivial.