Grooming - getting your hair cut regularly, wearing well-fitting clothes that aren't worn out, bathing every day - is also generally a bunch of optional habits, but if you want to be taken seriously and treated well in modern society, they are also needs. Some people choose not to invest as much time and energy into it and others can tell. It's treated as such an important signifier that many physicians make a note of it in your records!

For some people even social media is similar, because it's an essential tool for networking and getting business done. Terrifying, perhaps, but unfortunately true at this point.