Comment by imtringued

For those who might not understand the problem: deflation in combination with sticky prices makes it look like there is a glut of products for the supplier. Deflation also makes it harder to earn an income from work rather than sitting on your money, making it harder to buy foods.

Deflation is an opportunity cost to running a business. If you can earn x% from sitting on your money, then any business activity must earn more than x% before you consider the investment. The easiest way to raise the return on investment to match the opportunity cost is to sell at a higher price, but remember, you have deflation, so you can't pass on the cost to the consumers. Supply must shrink until the price is high enough to justify production again.

Reducing the supply of products also shrinks the demand for labor that is used in the production process, leading to more unemployment with sticky prices or reduced income with flexible prices. Reduced income means people have less money to buy products, which means producers see a lack of demand and reduce production even further. The downward spiral feeds itself.

Deflation is bad because it has acute symptoms. Inflation is the least bad option, because it's a manageable slow burn. Of course with acute symptoms you will see more action towards fixing the problem, whereas with a slow burn humans tend to drag it along forever.