How do parents feel if they've had one or more of their adult offspring living with them for awhile?

I know multiple people that live with their parents, from a 33 year old, to a 24 year old.

Some of the parents are visibly upset about it, and although I do not know everything about these families, I’ve noticed that some are more vocal than others to their adult kids. Some seemingly don’t care, and some say things like “Why are you staying here tonight, why don’t you go somewhere?” How would you feel if your adult offspring was still living with you? The reason why they are living with you obviously makes a difference, but what would cause you to start to be annoyed by their presence (if there is anything at all)?