Almost my whole life. It started when I was dissociating as a kid to blunt my emotions, then at one moment when I was a teen it went 24/7. The weird thing is when that happened I was doing allright. Since then it never stopped except for a few brief moments.
I got used to it eventually but it did annoy me in early days and no one understood me when I opened up about it.
World is basically a fog. I did enjoy it to a degree but nothing felt quite real. It is like having a good or bad dream, but it is always a dream.
Good comparison I read once was that it is like looking at the world through the veil.