The key to happiness is ensuring you put as little effort into your job as you can get away with. People don't lay on their deathbed wishing they spent more time in the office.

I have done a job before where I probably would be happy to put extra time in, but that is because its a job that involved helping other people rather than companies. A student that lost all their data and has a deadline next week - data recovered. That sort of thing actually feels good, sure I get paid to do my job but when you have a task like that it feels good to put more effort in.

Some megacorp needs their SaaS product updated, couldn't give a shit its 5:30 I am switching off. I guess there is also an argument there for finding a job that involves some degree of helping people, but the opportunities are rather limited and I need to do something.