Psychology says people who celebrate their birthdays alone aren't isolated, they may simply be choosing solitude over loud parties

Some people intentionally choose to spend their birthdays on their own. They might take a solo trip, enjoy a favorite meal, visit a quiet place, watch a movie, read a book, or simply set aside time to reflect on the year that has passed. For them, solitude is not necessarily about being alone, it can be an opportunity for rest, reflection, and personal meaning.

Raccontata daeconomictimes.indiatimes.com