People use sandpaper to make things smooth and beautiful.
Its most common purpose is used by woodworkers to sand off rough surface areas and round off sharp corners. Hours of work can go into a project to make it smooth and beautiful.
But, what if smooth isn't always the goal.
Amusement parks build outdoor steps out of wood for thousands of people to use every day, and they don't smooth off the edges. Instead, they glue a piece of ugly type of sandpaper onto the edge of each wooden step to create a rough surface.
This rough surface adds additional traction so no one slips and falls when they step onto each step. This works especially well when wood gets wet from rain or morning dew.
The higher someone gets on a set of stairs, the more severe the consequences become from an accidental slip and fall.
Smooth may work and look great in a perfectly controlled environment, but life isn't perfect. Life brings with it many potentials for slip and falls.
Rough gives you the added traction to move forward. Rough helps you to successfully deal with the unexpected elements that will come into your daily walk.
If the goal is to have everything go smooth, you have missed the benefits and opportunities that rough and ugly provide.