Richard Feynman said: The first principle is that you must not fool yourself — and you are the easiest person to fool.
How many times we say “Yes” to parties we don't really like to go? How many times we say “Good” to things that are not really good? How many times we try to keep a relationship that we know not going to work out? When we find we're convincing ourselves, be cautious, because we may be fooling ourselves by convincing.