Nope. Not emacs vs vim. The biggest thing is what kind of music. Also, what kind of slang. I know this because I was young once, too. When I got a coworker who was twenty years older than me, it made me uncomfortable. Weird 'dad' jokes. Musical references that were completely out of it. Stories about the past. I like people and I liked them but, it was also, always a little uncomfortable. We were peers but they, well, nobody is a true peer with a twenty year gap. Uncomfortable.

Today, hiring authorities are more likely to be young. They also feel uncomfortable with someone who has a huge amount more experience.

Ageism is real.