I would like to respond to this as well, fundposh! A long time ago, humans lived in tribes. If you were ever turned into an outcast of that tribe, most likely you would be eaten by animals or starve to death (or both). The fear of rejection is ingrained in us at a primitive level.

Sometimes someone will think a better idea... but everyone else is comfortable with the way they do things (a tradition, for instance). To bring out your idea means threatening the mental comfort of your tribe. This will possibly bring about rejection from your tribe. However, if the idea is good enough, eventually your idea will catch on and a bunch of people will end up scurrying over to the way you think so they don't get left behind.