Panic, the direct result of
1. Breathless reporting creating a crisis where none exists, and
2. Brainless, selfish sheeple filling when they don't need to and hoarding.
Just like when there was a perceived shortage of gasoline after Hurricane Harvey - news outlets reported that some refineries had shut down, and that shortages could occur; local TV station in Dallas hunted down one (1) gas station that was out of gas and led with that story in the morning news, flogging the story. And, the race was on.
People waiting in line for hours to buy gas topping-off their car that was 1/2 full; people buying out all the gas cans at every store that sold them, to fill them up; people putting gasoline into garbage barrels.
My own sister called me and asked if she would hurt her husband's car by putting regular instead of premium - I asked her how much had been in the tank before she added the gas, and she said "...a little over 1/2 tank." I asked her why she was filling it up, then, when hubby was out of state, and she said she had heard that there was a shortage of gasoline. I asked her if they were traveling soon, and she told me that they were off to Colorado the next day. on the airlines.
In disgust, I told her that she, and people like her, was the reason for the "shortage." She wasn't happy, but self-examination ain't always easy.
Before the "shortage," I had about 5/8 tank in my truck; when ready gas availability was restored, I had 3/8 tank. Woop.