There's a word for that!...of the day.
Well, to understand desire paths fully requires years of study in both human behavioral psychology, and human geography; but to offer a glimpse into their existence is rather simple. Desire paths are beaten down by many individuals (usually) and often connect two popular locations via the shortest possible route. This often doesn't fit the "design" elements of the parks.
So next time you feel you're falling off the trail in favour of a road less traveled, remember all those who stomped before you. Desire paths are essentially democratic trails voted on one step at a time.
Cheers to collective good and natural trails. Never follow the only beaten path!