The market is like a pendulum, forever swinging between unsustainable optimism and unreasonable pessimism.
If you let the ups and downs of the market dictate your emotions, you will definitely lose money.
Many times, it is not losses that destroy our trading psychology. What really hurts us are losses caused by unplanned, passive, lack of self-discipline, impulsive, and random trading behaviors.
The worst thing you can do when a trade isn't going your way is to act blindly. If you don't have a good opportunity in a trade, it's best to do nothing at all.