Few people other than economists understand the nature of prices. Essentially prices are bits of information which are conveyed between those participating in markets (all people whether buyers, sellers or intermediaries). 

Among other things it conveys what the best use of scarce resources are at any time and in any place. When prices rise to a certain level consumers of the product or service involved, unless the product or service is an absolute necessity (food for example), either curtail their usage of the product or seek alternatives.

Also, entrepreneurial types see an opportunity to profit and enter the market with innovations. 

Any attempt to control prices either by ceiling caps or flooring stops skews the information thus preventing all parties from gaining the knowledge they otherwise would from prices.

The results are misallocations of scarce resources and shortages.

To cite just one common example, if there is a hurricane in Florida, the price of plywood skyrockets. Demand increases the price if the supply remains constant.

The economically ignorant deride this natural occurrence as 'price gouging'.

If such people had their way the maximum price would be set by the government and there would be a serious plywood shortage, which would harm Floridians wishing to protect their property.

If prices are allowed to rise naturally, those who have plywood supplies in other areas would be watching the situation, and when the price reached a level where these suppliers could transport some of their plywood to Florida and make more profit than they could where the plywood is currently being sold, they would flood Florida with plywood until demand had been met and the price had returned to pre-hurricane levels.

This is why price controls are always and everywhere a very bad idea.