We can't be always right

Nice excerpt from How to Win Friends & Influence People book:

When Theodore Roosevelt was in the White House, he confessed that if he could be right 75% of the time, he'd reach the highest measure of his expectation. If that was the highest rating that one of the most distinguished men of the twentieth century could hope to obtain, what about you and me? If we can be sure of being right only 55% of the time, then we can go down to Wall Street and make a million dollars a day. If we can't, then why should we tell other people they are wrong? :-)