After a reader asked about why I don't use shower products on the cold showers post comments, I started thinking of other things people do or use that I find I don't need. Here's a short list, preceded by a disclaimer: I'm not a joyless robot, deranged workaholic, or dirty hippy, so don't start with the pattern matching of stereotypes and questioning of my humanity. I just like to experiment.
Dessert. I randomly decided to only eat one dessert (the French macarons at my wedding) in 2013, and it has been great. It's simpler this way: I never have to resist eating desserts, and I appreciate tasty non-dessert food more. Drawback: sometimes I have nightmares where I accidentally eat a cinnamon roll, or some baddies are chasing me and trying to shove donuts into my mouth.
Drinking things that aren't water. From an early age I never wanted to try soda or coffee, and this persisted to never trying alcohol, either. I eventually accidentally had a digestif on a romantic date with Chloe in Paris, but it was gross. I stopped drinking fruit juice because it's too sweet, milk because of experiments with cutting out dairy, and vegetable juice because it gives me gas. What else do people even drink? Tea, I guess--I drink that when Chloe makes it, but I honestly don't see much difference between tea and hot water. It's just easier to be content with water than to ever crave some other sort of beverage.
Shower products. I gave more details in this comment, but basically I found that after five weeks of not using shampoo, my grease production shut down and I no longer needed shampoo (just like the internet said would happen). I tested body wash on one half of my body for a while and so no difference, so stopped that. I cut out conditioner when I cut off my long hair, and I use a dry-shave electric razor, so I never used shaving cream. Showers are now quite straightforward.