Well that's what i like on playing on a server too, but not every server is nice to play on. I like to see bases from other players evolve and expand, and it's nice to have neighbours in the minecraft world. While some players choose to head out for -25k for example, but that's up to them.
About my singleplayer world, i like to walk around in creations i've made earlier on, see my way of thinking and way of building. Also I couldn't agree more with Ren's last video of his survival world season 5, where he spoke about memories and fases of life where he was in and getting memories triggerd by seeing those buildings back later on in the positive or negative manner.