"Is this the cause of James Dillon’s agitated state of mind? Yes, I think so. Some strong pressure is certainly at work. What is more, it appears to me that this is a critical time for him, a lesser climacteric—a time that will settle him in that particular course that he will never leave again, but will persevere in for the rest of his life. It has often seemed to me that towards this period (in which we all three lie, more or less) men strike out their permanent characters; or have those characters struck into them. Merriment, roaring high spirits before this: then some chance concatenation, or some hidden predilection (or rather inherent bias) working through, and the man is in the road he cannot leave but must go on, making it deeper and deeper (a groove, or channel), until he is lost in his mere character—persona—no longer human, but an accretion of qualities belonging to this character."
—
Patrick O’Brian’s Master and Commander.
Brought back to my attention by a friend who added this: “I’m going to do everything I can to avoid this, because I often feel like I’ve stopped evolving and am descending into a caricature of myself.”
Word.