Professionals built the Titanic. Conscience is what hurts when everything else feels so good.
Talk is cheap because supply exceeds demand.
Even if you are on the right track, you'll get run over if you just sit there. An optimist thinks that this is the best possible world. A pessimist fears that this is true. People will accept your ideas much more readily if you lie and tell them that Benjamin Franklin said it first. It's easier to fight for one's principles than to live up to them.