At least for adults - I mean they're alright for kids. Couple of years ago my kids stood me a pub lunch for mine. On leaving, and as my dodder was paying, the manager of the pub asked her whose birthday it was. She said, 'It's our dad's, and he doesn't usually celebrate his birthdays,' Quoth the manager to me, 'You don't celebrate your birthdays? Why's that?' Quoth I back, 'Because they're reminders we're a year closer to meeting the Grim Reaper - what's to celebrate?' He looked at me askance and said, 'Blimey, I'll bet you're the life and soul of a party!'
I suppose it all started when astrology took off. In modern times, they're probably mainly celebrated for commercial reasons, just like Halloween etc.. their real meaning vanishing. They're great for kids and then marking certain ones such as 18, 21, 40 etc.. But like any event as you get older, the novelty can wear off.
