Sure I feel weird sometimes, just less and less often.
I have two friends who are hugely into the Giant piles of presents mindset, so I will grudgingly give them one small thing, usually consumable, when attending a birthday do.
But for everyone else, and when invited to a party, I put the event on my calendar, plan my dog care and meal prep for that day, make sure I have clean and presentable clothes to attend, and in general treat the party as the main event.
And completely forget that I am supposed to at least buy a card. I've walked out our front door many times without even a card in my hand. I am just so NOT oriented to buying crap for adult birthdays.