That which does not kill us, makes us stronger. You can't make a fact out of an opinion by raising your voice. You can never destroy the Establishment, you can only replace it. If you do take over, you become the Establishment. Lead, follow, or get out of the way.
Every advantage has at least one corresponding disadvantage.
By working faithfully 8 hours a day you may eventually get to be boss and work 12 hours a day. It is better to remain silent and be thought a fool than to open your mouth and remove all doubt. You never get a second chance to make a first impression. If a committee or team is allowed to discuss a bad idea long enough it will vote to implement the idea simply because so much work has already been done on it. Don't be irreplaceable.