I have a feeling parents are going to downvote me, but I’m going with NAH.

I’m gonna say your not the asshole because I remember very specific times when my parents or grandmother tried their best to get my things I wanted for my birthday or Christmas and just missed to mark. I really appreciated them trying and never showed it, but they’d always realize it later when that gift just didn’t get used. Cash always eliminated that issue, so my grandmother especially just moved that way. Sometimes I’d buy myself something, and sometimes I’d just save it. Worked out great.

I say NAH though because I don’t want to say what made me happy should make another kid happy. And although your intentions may have been good, it obviously hurt your son a bit. I’d say going forward, do some research. Starts months in advance. You know when birthdays and holidays are- start thinking further out and get something that means a lot to him and he’ll happy.