The gravity of the loss is totally dependent upon how the loss was incurred.

Since trading is based upon probability of success, and there is not a 100% probability of a trade going in your direction, there will be losing trades.

If you had a trading plan that had a high probability of success, stuck with the trading plan to the letter, and the market moved against your position inexplicably resulting in a loss, that trade defied the probabilities and resulted in a draw down of your account. It happens, and you move on to the next trade.

If, on the other hand, you entered the trade without a trading plan, or altered the trading plan on the fly (I know this is going to turn in my direction so I will move my stop to give it some more room "to breathe"), then you are trading on emotion. Emotional traders are most often losing traders.

Profitable trading depends upon taking trades that have a high probability of success using a repeatable process to make trading decisions.

I would rather take a small loss when a trade goes against a proven trading methodology, than to have a winner based purely on luck. Luck is not a repeatable process.