[jeroenhd]

Some people have the energy to do two jobs at once even if they don't strictly need the money to survive (like many minimum wage workers do); if they can keep themselves in check, that's a great way to make more money and build up a comfortable life or prepare for an early retirement.

It's not for everyone and it's certainly not the standard. There are also people who work themselves to death and pretend to be fine. I'm sure it _can_ be healthy and fine if that is what you want; it just shouldn't be expected of people.