It's where I can see people that I don't see anymore. It's like a memory bank full of counterfeits, but I can study the copies to help me better understand the real ones. There's probably a danger in confusing the two.
Emily Haines's song, Nihilist Abyss just came on and the song illustrates it pretty well:
When I walk alone I'm walking with you
When I sleep alone I'm sleeping with you
It's difficult holding so many people in your head all the time. With dreams, it's almost manageable. Even if it means letting them go all over again.