A sober individual's brain is operating on standard (often societally installed) reward mechanism, including "succeeding" on certain self-evaluated measures like "contributions to society"
It's commonly said that weed makes you "OK with being bored". i.e. standard reward mechanisms mentioned above don't really matter much when you're high.
It has nothing to do with narcissism or sense of superiority as you call it, just that their reward mechanism doesn't include things like "how much am I contributing to society". Apathy is a better word for it.