In your living room this is.
YANBU = i have my own chair (and no one else sits in it)
YABU = we all swap around and everyone sits anywhere.
Further more (if you like to elaborate) :
- Do the whole family have their own chair?
- What happens if you get fed up with 'your' seat. Is it tough luck?
- Do you have control over moving the furniture round if you get bored or do you have to have a family conference about it?