I don't know about "spending a lifetime", but I was fascinated by Transport Tycoon Deluxe as a kid and remember playing it once even as an adult. Besides this,

I don't know about "spending a lifetime", but I was fascinated by Transport Tycoon Deluxe as a kid and remember playing it once even as an adult. Besides this, I enjoyed the Grand Theft Auto series, Football Manager, and The Sims. These days, I don't play at all despite having a PS4 lying dormant. I'm not sure why, but if I had to pinpoint an exact reason, perhaps it's the feeling that I'd be losing out on the chance to spend that time improving myself.