What needs aren't actually needs?

A few months ago I stopped using my last hair product: shampoo…and found out that I like my hair infinitely more and spent infinitely less time on it (and money) when I just wash it with water.  It makes me feel unjustifiably badass knowing my hair would not be giving a shit in some sort of Mad Max/zombie apocalypse scenario.  But it also makes me wonder what other sorts of things we’ve always treated as absolutely and completely essential, when they actually weren’t.