I discovered today that my most played game on Steam is Astronner with about 500 hours, and my second most played is Surviving Mars with about 500 hours.
Before the community died off I had put just under 20,000 hours into Subspace / Continuum (mostly on EG). No, that's not a typo. I learned what addiction looks like as I grew older.
Between that, NexusTK, The Realm and an unhealthy obsession with SNES JRPGs I don't know how I managed to make it through grade / high school...