Unless at some time you change your ideals and opinions and decide you would want to forget that time or you regret how it changed your life.
Sorry, that was response to two people's different comments in one sentence, most confusing.
I quite like the various celtic knot designs, but I can't see any reason to get something that other people have. I am quite intrigued by a lot of Chinese philosophy, particularly I Ching - the book of change, but having something to symbolise that wouldn't necessarily reflect anything.
Obviously if I were to get a tattoo it would be for myself not because of what someone else might think, but satisfying what I would think is appearing to be a major problem at the moment.