Definitely not everyone but it feels to be a large percentage feel that -
You only should celebrate your birthday until you are 10. Anything after that and it's odd.
Why are you buying Christmas presents for adults, only buy for children? So not adults aren't allowed presents at Christmas.
Going out on a Saturday night even for just one drink seems very frowned upon and
Life as an adult is pajamas on at 7 every night of the week, not celebrating your birthday and not getting presents at Christmas.