Where does potential energy come from?

Potential energy comes from the buildup of pressure or stress. lets say, for example, that a rubber band is being stretched and then kept at its max stretching point. at this point if it is to be let go, it would fly off. why? because of its potential energy turning into kinetic. the stress of the rubber band being stretched gives it the potential energy to turn into kinetic, therefore causing it to fly off. i hope this helps :)