When someone does something deceitful to you, you forgive them, and they take your kindness as a weakness and think they have the upper hand. Now you turn around and do the exact same thing to them, but they never see it coming because they thought you were weak! Gotcha.
Mike made plans with me, later confirmed the plans, seemed really excited about everything and called two hours before to cancel, turns out he had no means to keep the date from the start. I laughed it off, accepted another date and flip the script, this time I no-showed for the date.