> ie if you take breaks from work and instead of wasting time on HN or reading news you bang out code on your personal projects, I'm not going to be enthused about that. But if you generally work 10-6 or so, and by 610 you've shut our laptop and you're coding away on your personal laptop? Great, have fun. Please don't burn out.
That works well enough for employees who work 8 uninterrupted hours per day 5 days per week as their work week. (Even for them, sometimes copyrightable personal projects are different enough to serve the same mentally restorative purpose during the workday that browsing the Internet can, like if it's poetry or designing a sweater.)
But not everyone performs best or happiest like that.
What about the employees that typically work 11-2, go for a gym break 2-4, work 4-6, go for dinner and time with their family, and then work 8pm-2am... but mix some personal side projects into the 8pm-2am part and think up advances on those personal projects while at the gym, plus do extra work for both personal and employer purposes on weekends?
Yes, these patterns are consistent with people I know in the industry. (I'm combining multiple people for anonymity.)
Notice those hours added up to well more than 8 work hours per day and more than 40 per week. If such people can't interleave personal and work stuff, they'll probably spend less time on work stuff overall and give less productivity to the company (if they don't switch to a more permissive employer).