You were there, it was real. The memories are real. The spaces are real even if not corporeal.
For me it's places from my childhood I can still visit without feeling alienated. If I visit my childhood home that we sold decades ago, there's someone else living there and I don't see with the same eyes either. But the multiplayer maps are the same.
I play the FOSS FPS called Xonotic now just for the entertainment. I realize I was never as good as teenager me believed I was. But I can learn. Sometimes when I'm gibbed early in a Clan Arena match, waiting for the round to end, I'll just rise to the top of the map and see the fake sunrise backdrop of my childhood. I can also recommend defrag mode, just running around a track parkour style trying to maximize efficiency is extremely relaxing.
Gotta wonder if this could be used to improve elder care for our generation. Imagine being in an old folk's home with VR headset and playing with your peers in familiar surroundings?