A bluebird flies against a truck mirror countless times.  Hour after hour he repeats his attempts at chasing away the reflection of himself that appears in the mirror.  It is funny to watch but also saddening.

 His efforts are staggering and his accomplishments minimal.  And, he has no idea about why he is enduring this effort.

 Oh, he is pissed off.

 Imagine doing a task that you had no idea about the purpose and all you knew was that you had to keep trying ---- to accomplish what?  Such is the animal world.

 He is struggling so hard to accomplish nothing.