Exactly this

Exactly this. I worked for a place long ago, where we had this junior guy who basically didn't have a life. He just wanted to code. He stayed late every day, and would occasionally come in on the weekends and code all day. He was not making any extra (in fact since he was junior he was probably making much less than the rest of the team). He was not angling for a promotion from what I could tell. He just liked to code and that was his entire life. Well, his manager gave him some public praise once over E-mail, basically saying the project was moving along much faster due to how productive you are. That's all it took. Suddenly, the whole team felt pressure to pull 60-80 hour weeks and burn themselves out. And we didn't really get that much more done, because it was 80 low-quality burned out, demoralized hours, not 40 high-quality hours. The team eventually disintegrated along with the company during one of the tech downturns. All that wasted stress because one guy doesn't have a family or hobby.