I love to have deep, hot baths and DH and DS do too. To enable us to have them really deep and not feel too bad about wasting water, we share the water, one going in after the other (or sometimes one of us shares with DS). I happened to mention this to my DSis who thinks its absolutely disgusting.
Obviously if I'm shaving then I'll go in last or if anyone's particularly dirty they go to the back of the queue, but this is normal behaviour isn't it? Does everyone else share bath water or AIBU to share bath water with my family?