I have meditated once in my life so far and to not intend to again. I had enlisted for a class on TM in 1975 or so. The person who initiated me gave a supposedly secret mantra specially created and warned me never to reveal it to any one. Later on comparing notes with other friends we found that he has only four mantras which he assigns at random and tells every one that it is a tailor made one for the particular person!
I meditated for a few days and realised it was a waste of time.