Permit me to set the stage because the illustration is lost without a little background. It's worth it: trust me.
THE ROMAN BATH:
Roman baths were an integral part of the Roman community. This was the place to socialize, exercise, relax and to simply get clean.
After paying a small fee and dropping off one's clothes, one could visit the "frigidarium" (cold bath), then the "tepidarium" (warm bath) then the "caldarium" (hot bath). Many also enjoyed the "palastra" (excercise area) that might have included something like a swimming pool and exercise equipment.
Seneca wrote a letter to Lucilius that gives a humourous description of what life was like living near a bath-house. See if you can picture the scene in your mind:
My dear Lucilius,If you want to study, quiet is not nearly as necessary as you might think. Here I am, surrounded by all kinds of noise (my lodgings overlook a bath-house). Conjure up in your imagination all the sounds that make one hate one's ears. I hear the grunts of musclemen exercising and jerking those heavy weights around; they are working hard, or pretending to. I hear their sharp hissing when they release their pent breath. If there happens to be a lazy fellow content with a simple massage I hear the slap of hand on shoulder; you can tell whether it's hitting a flat or a hollow. If a ball-player comes up and starts calling out his score, I'm done for. Add to this the racket of a cocky bastard, a thief caught in the act, and a fellow who likes the sound of his own voice in the bath [singers and poets], plus those who plunge into the pool with a huge splash of water. Besides those who just have loud voices, imagine the skinny armpit-hair plucker whose cries are shrill so as to draw people's attention and never stop except when he's doing his job and making someone else shriek for him. Now add the mingled cries of the drink peddler and the sellers of sausages, pastries, and hot fare, each hawking his own wares with his own particular peal. ... (Letters, 56.1-2)
NOW, THE LESSON:
"When you are going about any action, remind yourself what nature the action is. If you are going to bathe, picture to yourself the things which usually happen in the bath: some people splash the water, some push, some use abusive language, and others steal. Thus you will more safely go about this action if you say to yourself, 'I will now go bathe, and keep my own mind in a state conformable to nature.' And in the same manner with regard to every other action. For thus, if any hindrance arises in bathing, you will have it ready to say, 'It was not only to bathe that I desired, but to keep my mind in a state conformable to nature; and I will not keep it if I am bothered at things that happen.'" (Epictetus, Enchiridion 4)
The evident lesson builds on what we've learned already: what is within one's power to do and is reasonable to desire? If we were to use a present day illustration, one might say that the nature of an action must be "front sight focused." Have a single mind behind an action. Stay on target. What is the target? "keep my mind in state comfortable to nature." Tranquility.
At the shooting range, the weapon lined up with the target does it's best work. This means that one understands the mission, the objective as well as maintains an awareness of surroundings. Why not the "shotgun" approach? Behind all this is self-mastery, self-control, tranquility of mind and heart.
In the ancient illustration of taking a bath, be sure to note that the bath might get interrupted--that's not the objective. The objective is the state of mind.
CONCLUSION:
So when you go to Wal-Mart and get cut off, play "ring-around-a-rosie" with the Shopping Cart Cowboys, nearly get run over by the stocking crew, can't reach what you want from the top shelf, have to wait for the deli person to get off their break, wait in line for 15 minutes before the clerk declares the line is now closed and you have to find another . . . what was the goal again? Oh yeah--don't let things get to you.
