Riding Rough

Riding a rough horse—

Cannot be reined in.

Jumps the fences,

Lands hard on stony ground.

Shoots along flat faceless land,

Ducks under spiny trees,

Sweeps through sage brush.

Won’t let rider dismount, no, no,

Wind chapped, finally brakes cold,

Shakes head, nickers, and tosses mane,

When the rider. 

Slams. 

Down.

What do you think this poem is truly saying?