Are those who simply work, mind their own affairs and forgo social functions perceived negatively at work?

It definitely depends on where you work. I usually didn’t want to socialize with my co-workers, we rarely had anything in common and it seemed like a recipe for unnecessary drama. But when I accidentally befriended someone in upper management who’d once been a musician, it ended up fast-tracking my career and I got promoted.
The adage about it being “who you know” is not totally wrong.