regret of missed opportunities, of missed pleasures..
frustration at the unfairness of it,
torture a man..keep him running, keep him from breathing,
he cannot accept a world where his desire is not met,
it is unbearable.

He is in a nightmare, running away from a monster and chasing a beautiful princess.
The memory of her beauty and the ferocity of the monster keep him consumed in chasing and running.
He has the idea in his mind `The only real solution is to wake up!'.. but he does not know if he believes it right now.
To see if it is true, he must stop and sit, at the risk of losing the princess and being eaten by the monster.
Sit and return to the basics.. what are the basic realities?
There is pain, and freedom from pain.. at the depth of his experience those are the only options.