The wearing of underwear under pjs is a matter of personal preference. They wear whatever is comfortable for them. Then too, it depends on why they are wearing pajamas. Most people here in the west use pjs mainly for sleeping and may or may not wear underwear with them. However there are some cultures that wear pjs as lounging attire at home and these people more than likely would wear underwear beneath the pajama.
Some people do, but most people wear underwear.
Asian ladies can wear underwear under their dresses. Most Asan ladies do not wear underwear.
Yes, nuns as well as most people wear pajamas.
Yes, bras are considered underwear. Most people do not share their bras with other people, and keep them private.
Yes, yes they do.
Naval terminology for underwear. Most people I know use the term to refer to thermal underwear.
A lot of people found the ending interesting...
They only wear their underwear under their suits, it's a jumpsuit
Yes, most people do in jail just as outside.
Most Women wore dresses under dresses and underwear.
Wear pajamas to sleep. Most people do.
Most people don't want to see your underwear