| Quote #1
"Possibly," you will add on your own account with a grin, "people will not understand it either who have never received a slap in the face," and in that way you will politely hint to me that I, too, perhaps, have had the experience of a slap in the face in my life, and so I speak as one who knows. I bet that you are thinking that. But set your minds at rest, gentlemen, I have not received a slap in the face (1.3.3)
Either the Underground Man is speaking literally and has never been challenged to a duel, or he is speaking metaphorically and has never truly been offended. The latter carries much weightier implications; it would suggest that he knows his attempts at revenge have been pointless and irrational.
| Quote #2
Of course I have myself made up all the things you say. That, too, is from underground. I have been for forty years listening to you through a crack under the floor. I have invented them myself, there was nothing else I could invent. It is no wonder that I have learned it by heart and it has taken a literary form....
The Underground Man is so isolated that even these Notes – his one opportunity to communicate with the world from underground – are a solitary endeavor.
| Quote #3
I did not, of course, maintain friendly relations with my comrades and soon was at loggerheads with them, and in my youth and inexperience I even gave up bowing to them, as though I had cut off all relations. That, however, only happened to me once. As a rule, I was always alone. (2.1.9)
The Underground Man makes it clear that his flight to the underground was a long time coming. At no point in his life has he ever been at home in society. This definitely affects the way we look at his character. Rather than trying to find some reason for his isolation, some specific event, we attribute his solitary confinement to his unchanging character.