is probably right on point.  I suspect for many traders, the fear of a loss is what holds them back.  Seen this phenomenon ad infinitum at the racetrack.  People playing with scared money or letting other "baggage" find its way into their decision-making process...seeking reassurance before they place their bet. In the case of trading, instead of properly assessing risk/reward and acting accordingly, the psychology of "not wanting to lose" often impacts one's ability to take the trade.

There's a fine line between entering a position early or at just the right time vs "being late".  Just my opinion, but I think what holds us back from time to time is that we find it difficult to trust our instincts; instead, we seek some form of guaranty that doesn't exist.  Intellectually we know better, but trading is more about psychology than it is about intellectual pursuit.