I read somewhere that it was important for a Buddhist monk to make his bed when he arose from his sleep. 
At the time I thought it was because this activity kept the strict regimentation of the monk’s life of study and service. I was correct in a way, but not fully.
Arising from sleep and waking from the dream state is stressful for the body. Muscles need to stretch, joints need lubrication, a massive steam locomotion shunting slowly from the sheds to the tracks of its next journey.
Why make your bed?
Because the act is very symbolic of life itself. 
Arriving into the morning like a newborn, blinking in the sun. The covers still swaddle, but soon become a burden. Stretch, breathe deeply and shake off the energies of sleep as many animals do. They know the new day has begun.

Make your bed, for it represents your mind as you begin the first day of the rest of your life. Stale, cloying darkness or bright, clean folded comfort? The choice is there for all.

The activity can be sacred and when carried out almost as a ritual, it will create a place of joy to return to each night. Surely returning to a place of solace and reflection should be a journey to look forward to. Finally reaching this destination is an achievement, a goal when faced with the density that can feel like our lives.

So plump the pillows.
Straighten the wrinkled sheets.
Air the bedclothes.
Make ready for the next night’s journeying. Another dreamscape adventure awaits. You may or may not remember it but you will sleep soundly in the wholesome headspace you have created.