People usually celebrate their birthdays. It’s an accomplishment of sorts: being born and being alive. However, I find it somewhat odd, seeing as I didn’t actually do anything to achieve my birth or state of living. Luck allowed me to have two parents that decided to have a third child, the genes to not get significantly ill, and the fortune to not be in any tragic accidents.
So birthdays are a celebration. But they are a celebration of everything that we are grateful for.