Happy as in “all absolutely necessary for survival bills are getting paid on time, all outstanding debts are getting paid down regularly, and I can afford to eat at a restaurant slightly above fast food grade once a month or so?”
$308,740/yr for the first year would do it.
After that I could probably look at halving the salary and live, if not comfortably, at least without constant worry.
Maybe start putting something away so I can retire before I hit 70.
Happiness doesn’t come from money, but it sure would reduce stress.