This quote has fascinated me for a long time. It seems that this is a skill that can be sharpened with deliberate practice. I went to a 10 day silent meditation retreat (Vipasana) abs felt I got much more comfortable sitting by myself just observing my thoughts. The practice part was difficult, probably one of the hardest things I have ever done. 10 days of no talking/reading/writing, sitting in a room, observing you…
A very very corny way I like to think about this is the separation of the init process (being) from other processes (thought, sensation etc.). I know this is a very superficial interpretation, but I find it helpful.