"Who ain't a slave? Tell me that. Well, then, however the old sea-captains may order me about--however they may thump and punch me about, I have the satisfaction of knowing that it is all right; that everybody else is one way or other served in much the same way..."See in text(Chapter 1 - Loomings.)
Ishmael is used to people making fun of him because he desires only to be "a simple sailor." Here he states that each and every person is a slave to something or someone on the earth. Therefore, what is the harm of obeying a few orders from someone with high rank and high responsibility (hence high stress)?
"I go as a simple sailor..."See in text(Chapter 1 - Loomings.)
An important part of Ishmael’s character is revealed here. Ishmael never desires a grand name or a grand rank or a grand result from his adventures on the sea. He only desires to be a “simple sailor.” However, Ishmael is far from a simple person. His narration reveals that he actually remains deep in thought, constantly examining events in his cerebral, exuberant manner.