Probably because they were scared of losing their job and were being asked to work harder.

Or they are a self motivated high achiever.

Didn't seem to make a difference here.

This is a case study of the futility of intra-corporate "high achieving" when you can be laid off on a whim regardless of performance.

Layoffs can be random, but promotions rarely are. It’s not necessarily a bad play.

Or they have fun coding.

I have fun coding. I can't get out of work fast enough. Partly to do my own coding.

I have fun coding. I can't wait to dig into interesting problems and figure them out - regardless of if it's for my own coding or my employers.

Ah yes, jumping to conclusions without letting the parent commenter reply. Genius.

This is apparently par for the course at Stripe.