Trading Discipline!
This is what differentiates a Pro 100% mechanical system trader from an Amateur wannabe 100% mechanical system trader.
The Pro is on the golf course and doesn't care if the system loses or wins on the current set of trades, even if he had a strong feeling about the current trades being losers. He knows there will long periods when the system doesn't make money and thats all an expected part of the system design.
The Amateur is glued to his screen and ready to interfere with the system because it is on a losing streak and he cant handle the pain of anymore losses.
This interference will just make the losing streak last even longer, in fact he will just end up abandoning the system and start changing its parameters or start playing other 'games', effectively throwing all discipline out the window.
The Pro has developed a discipline hack, he doesn't even look at the trading screen during the day. Although he might need some discipline to not do this. The temptation is to look at the screen if you are bored and have nothing to do. This serves no useful purpose except entertainment to alleviate boredom. But can prove very expensive. Cheaper to find a hobby that keeps you busy.