The person beginning again in a new place is carrying a history the room has not met.

Starting over means being read entirely from the present. The new colleague arrives with decades behind them that nobody in the room can see, and gets treated as whatever they appear to be today. That is disorienting in a specific way: not unkindness, just the strange lightness of being known by nobody.

When someone is new to your place, ask about before. Not the resume version but the ordinary one: where they lived, what they did on Saturdays, who they miss. And if you are the one starting again, tell someone one true thing about your old life early, so that a piece of it exists here too.