Meaning of abnormal mind and wild in the chapter 1 of The Great Gatsby

'd like to know the meaning of some words of this excerpt of The Great Gatsby, chapter 1: does "abnormal" refer to a deviation from typical norms? Does "politician" mean "manipulator" does "wild" mean "unconventional"? Is "quivering" a metaphor evoking a sort of "mirage":

The abnormal mind is quick to detect and attach itself to this quality when it appears in a normal person, and so it came about that in college I was unjustly accused of being a politician, because I was privy to the secret griefs of wild, unknown men. Most of the confidences were unsought—frequently I have feigned sleep, preoccupation or a hostile levity when I realized by some unmistakable sign that an intimate revelation was quivering on the horizon—for the intimate revelations of young men or at least the terms in which they express them are usually plagiaristic and marred by obvious suppressions.

Thank you.