I remember one Star Trek writer theorizing that the Klingons were so cranky because they never put toilets in their ships.

I loved Babylon 5. One minor reason was because a scene was filmed in a restroom. With ultraviolet lights used in place of water for the handwashing. A sign that the characters are living in The Future. Showrunner J Michael Straczynski did this specifically as a small dig against Star Trek.