‘time is money’ and ‘money is time’

[Thegreenpotter]

How important is a work life balance? Do people live to regret working excessive amounts?

Impossible to answer ... some do, some don't. If you have an interesting, fulfilling job, like your colleagues, have a good relationship with your manager, feel appreciated, have autonomy to make decisions, a pleasant working environment etc etc and feel that your job is 'contributing to society' (or whatever other values you have) then going to work isn't necessarily a 'chore'.
Not everyone has a happy, calm home life ... so work might be preferable to being at home.