Because I experienced Oct 2018. I was long during that time. Futures contracts have expirations. If I had held onto the Dec 2018 NQ contract, it would have devastated my account. But I exited at my risk tolerance level. This can now happen at any time, can start a down trend on any day.
Remember, I am a perma-bull. I am not a perma-bear. I was taught and learned equities during the salad days of 2014-2017. Yes, Aug 2015 and Jan 2016 kinda' sucked, but was manageable. But these new swings are not what I was prepared for. Still working on it!
You may belong to a select majority of special traders who at every point in time end up in positions on the wrong side of the market, and reverse when the market reverses.
Best known remedy is to cease trading altogether and instead earn ze big bucks through coaching and psychology classes!