Rule # 7 on being a profitable trader: Let Go Of Losing Trades.
This is obviously the corollary to Rule #6: Hold on to Winning Trades.
As I have said before, this is all part of trading with Expected Value.
So if the goal is to maximize the gain per trade and minimize the loss per trade (as well as your winning trade %), over a large number of trades, then the act of letting go of losing trades is simply minimizing the potential loss of a particular trade.
There is always another trade.