Firstly you don't want be a drab motherfucker.
Style and expressions reveal feelings at the core that you want to convey. While many a time I preach the art of formlessness (in essence possessing no singular behaviorial patter but rather the skill set necessary to assimilate into any group) it's imperative that you have a firm grip on your personal identity.
For a long time I cared so much about a great multitude of things, I cared about people who hadn't the slightest inclination of concern to reciprocate, and it ate me alive. I cared about events that would transpire in the future and in a meticulous manner I'd analyze all of these scenarios, this would just manufacture stress. So then I embraced apathy. And all was good for moment but then I realized something. Life was lacking in luster. It was plain. Yes it was nice to acknowledge I didn't give a fuck but then what was there. What was there to inspire joy?
Yes, just a touch of madness. A gleam in your eyes. A skeptical uncertainty is inspired in others. They can't figure you out, they don't really ever know your intentions. You become interesting, spontaneous, eccentric. Your charisma grows and you stand with a newfound sense of authority. For you don't live. You Live.