Me time might be one of the few reasons that they are seen as mean moody and nonexpressive but in reality they’re just taking care of themselves. Cats say ‘No’ assertively when they have to. Disturb them and you’d know how sharp their nails and teeth can be. Give them space and they’d come out of their space looking for you to cuddle them.
Cats use this me time to sleep eat play and groom themselves and they follow this routine religiously.