I'm playing on this server that simulates the apocalypse, with a chat that has a range of only 100 blocks and no rules. As a rule when I play by myself on that server, I never ever build above a height of 40. The server supports 120 players, so you get gangs of 30+ people, all focused on raiding, pillaging and griefing. I have to use Skype to talk to my friends when they visit my base, in fear of someone hearing me. Other bases, entirely or partly above ground, completely destroyed for no reason. They didn't even steal my stuff.
Every now and again when I scour the above world, searching for the few groups of people who protect each other from griefing, I come across abandoned fortresses, castles oozing with lava, some foundations and a broken radio tower. I built my rather large base, now spanning thousands of blocks, directly under the main base of the biggest anti-raid organization on the server, hidden by a door submerged in lava. It's all gone now. It's lonely down there, on a pile of riches but no one to share them with.