Comment by samvher

You're right that it wouldn't be as easy for different kinds of jobs and working in a bar is a good example. Even there though, I think you could be clever about it - you can find opportunities that blend in with your work (e.g. coffee foam art, small talk in a language you're learning). These probably wouldn't increase your value as much but with some creativity I'm pretty sure in most jobs there is some kind of opportunity for learning.