I cancelled my birthday in September this year.
I was so ill at that point stuck in bed 24/7, I just didn’t want any celebrations/presents/etc. I couldn’t eat anything, I was deeply depressed not knowing what was wrong with me, struggling to pay bills when I could barely work, and it was MY birthday, after all. I didn’t want to feel worse than I already did. So, cancellation. (I do this periodically.)