"...the great paradox of morality is that the very vilest sort of fault is exactly the most easy kind. We read in books and ballads about the wild fellow who might kill a man or smoke opium, but who would never stoop to lying or cowardice or 'anything mean'. But for actual human beings opium and slaughter have only occasional charm; the permanent human temptation is the temptation to be mean. The circle of the traitors is the lowest of the abyss, and the easiest to fall into. That is one of the ringing realities of the Bible, that it does not make its great men commit grand sins; it makes its great men (such as David and St. Peter) commit small sins and behave like sneaks.
Dickens has dealt with this easy descent of desertion, this silent treason, with remarkable accuracy in the account of the indecisions of Pip."
From p. 28 of Critical Essays on Charles Dicken's Great Expectations, G.K. Chesterton, quoting from GKC's Charles Dickens. Another random discovery while poking about in the library's English literary criticism cases.