| Quote #1
It was not only that I could not become spiteful, I did not know how to become anything; neither spiteful nor kind, neither a rascal nor an honest man, neither a hero nor an insect. Now, I am living out my life in my corner, taunting myself with the spiteful and useless consolation that an intelligent man cannot become anything seriously, and it is only the fool who becomes anything. Yes, a man in the nineteenth century must and morally ought to be pre-eminently a characterless creature; a man of character, an active man is pre-eminently a limited creature. (1.1.6)
When the Underground Man speaks of "the intelligent man," he means a man of the same sort of hyper-consciousness as himself. A hyper-conscious person is never sure of his motives and so he doesn't feel comfortable taking action. Thus, according to him, if one can't act, one can never become anything.
| Quote #2
I swear, gentlemen, that to be too conscious is an illness – a real thorough-going illness. For man's everyday needs, it would have been quite enough to have the ordinary human consciousness, that is, half or a quarter of the amount which falls to the lot of a cultivated man of our unhappy nineteenth century, especially one who has the fatal ill-luck to inhabit Petersburg, the most theoretical and intentional town on the whole terrestrial globe. (There are intentional and unintentional towns.) It would have been quite enough, for instance, to have the consciousness by which all so-called direct persons and men of action live. (1.2.1)
The Underground Man seems to flip-flop between a desire for half-consciousness and the insistence that his way of life is superior.
| Quote #3
Tell me this: why does it happen that at the very, yes, at the very moments when I am most capable of feeling every refinement of all that is "sublime and beautiful," as they used to say at one time, it would, as though of design, happen to me not only to feel but to do such ugly things, such that ... Well, in short, actions that all, perhaps, commit; but which, as though purposely, occurred to me at the very time when I was most conscious that they ought not to be committed. The more conscious I was of goodness and of all that was "sublime and beautiful," the more deeply I sank into my mire and the more ready I was to sink in it altogether. (1.2.2)
It looks like the Underground Man is justifying his desire for self-inflicted pain. Happiness, he says (or at least "the sublime and beautiful," which is the closest this he gets to happiness) is an excuse for sinking into mire – so he's setting up a vicious cycle. He's disallowing himself any opportunity to be normal.