Solitude can reveal how much of your personality was adaptation.

A great deal of personality is response. You become slightly different around each person, adapting to what works, what is expected, and what keeps things smooth, and after enough years it is hard to tell which parts were adaptation and which were you. Alone, the responses have nothing to respond to.

Notice what falls away when you are by yourself for a stretch: the energy level, the humour, the opinions. Some of it you will miss and want back. Some of it you will recognise as effort you have been making without knowing. Both are worth knowing about.