Sometimes, even the best stocks get hit hard by broader market sell-offs, and it's natural to wonder why, CNBC's Jim Cramer said.
But most of the time, it's not because of some underlying weakness in the stock that investors didn't catch.
Nowadays, market sell-offs can happen because of index futures rather than actual fundamentals, an action that the "Mad Money" host said seems "at best stupid and at worst corrupt" and can drive investors crazy.
"The truth is, your inclinations are right and the action is every bit as stupid as it appears. There's no way to think of it other than negatively," Cramer said.
That's why investors need to remain level-headed in the face of widespread downturn. All markets will eventually go down, but you can make those declines work for you, not against you, Cramer said.
These days, S&P 500 futures run the show, and investors should never flinch at stocks going down despite strong fundamentals, he advised.