Always felt a bit eeew re people shlepping around in the festering garments they have just slept in all night. Maybe I'm a bit uptight in the pj department tho'
My own nightgarments are unflattering and not terribly modest so would rather shoot myself than wear them whilst making polite chit chat with the IL's over tea and toast, bra or no bra.
if you're staying at someone else's house you probably have no choice but to get dressed at SOME point during the day, so why not just get it over with when you get up?