After many years of experience, I realized that losses are part of the proccess trading. Losses happen to the best traders. The best traders I know do not have a 100% win rate.
When I take a loss, I sit down in order to:
a) review the trade
b) learn from my loss
What do you do when you take a loss?
Understanding that losses are part of the reading process is a big lesson, in fact the most important lesson to learn as a trader. Such realisation helps you guide your decision making because you will always have it in mind that nothing is guaranteed in trading.
The best of strategies are not 100% when rate and anyone who promises or claim to have such a win rate is a scammer. A win rate of at least 60% should be the target of every trader provided the risk to reward ratio is 1:3 and upward. With this the trader is on his way to enjoying a life of affluence.