'Detaching' seems like a cold and heartless word, like you don't care about anything or anybody around you. But I've found that if I 'detach' at the appropriate time, it leaves me with a sensation of blissful peacefulness.
I get uncomfortable in crowds, so I tried my detachment technique. I was walking downtown, with people everywhere. But all I focused on were the sound of my footsteps. I kept a steady pace as best as I could, and that 'rhythm' was what I focused on. I felt incredibly relaxed, despite the fact I was surrounded by people in a busy city setting.
I realize now after reading Story Theory that the reason this works (the calm feeling I got from focusing on my footsteps) is because you're using your mental resources to focus on a single thing, thereby blocking out the constant flow of automatic thoughts that swarm through our heads. By blocking those thoughts, my mind was left with a feeling of emptiness, bringing with it a feeling of deep calm.