I think we all have if we buy/sell stocks at all. The posters with little credibility, IMO, are the ones that seldom, if ever, mention a loss. Most of the Pro Pumpers at IHub are like that, IMO.
Worse case for me was selling DNDN before it took off back in 2009.......but hey, some bought it at 30-40 and lost big time.....
Cash is King until further notice!!!
My comments on companies are usually my opinion of long term success (years). The PPS may go up or down greatly in the meantime depending on the number of greedy fools with money.