A truth I would not like to tell, and that (as generically as I can express it) I cannot imagine anyone wanting to tell, would be "Exactly why do you feel most guilty about whatever it is that you feel most guilty about?". Similarly, a highly generic dare anybody would not like to have to perform would be "Try harder than you have ever tried before to conquer the fear of whatever it is you fear most". If you are unprepared to answer that truth or perform that dare, and I'm sure it's possible to compose equally generic fates that are less pleasant still, you should never play "Truth or Dare". I would be most unwilling to do either, so have no desire to play the game for the reasonable fear that either challenge might be imposed upon me - and I am most emphatically not challenging you either to tell me that truth or perform that dare on my account.
I can understand daring sporting pursuit of superlatives - first, fastest, highest, youngest, longest, most. I applaud those who seek to innovate, or those who push back their own barriers in the course of self-improvement. Nevertheless, proving yourself to be daring simply so that you have proved yourself in some sense more worthy, by some metric of worth, than those who are not prepared to take the same challenge strikes me as a very arbitrary and unproductive sport. Climbing Everest "because it's there" is noble in a way that a probably-drunken party game that sets out to remind people of their failings, or to demonstrate just why something happens to be conventionally regarded as foolish, is not.
There aren't any anecdotes I'm hiding or leading up to here; I'm just sayin'.