The need to use a bathroom varies greatly from person to person and even the same person's need varies depending on a variety of factors. My friend's wife refers to the first pee after a few beers as "breaking the seal". It always seem the need comes again soon no matter how long you've held off the first one.
I'm sure most pax don't use the lav unless they have to. But of course, there must be some who find the small space comforting or otherwise enjoyable. It really does take all kinds.