"Why must you invariably be the first to move aside?" I kept asking myself in hysterical rage, waking up sometimes at three o'clock in the morning. "Why is it you and not he? There's no regulation about it; there's no written law. Let the making way be equal as it usually is when refined people meet; he moves half-way and you move half-way; you pass with mutual respect."
But that never happened, and I always moved aside, while he did not even notice my making way for him. (2.1.24-5)
The Underground Man is offended because he has stubborn principles rather than because he feels truly inconvenienced; he doesn't really mind moving aside, it's just the idea of being somehow lower than the officer that bothers him.
But my preparations took a great deal of time. To begin with, when I carried out my plan I should need to be looking rather more decent, and so I had to think of my get-up. "[…] I must be well dressed; that inspires respect and of itself puts us on an equal footing in the eyes of the society." (2.1.26)
Notice how he attempts to be on equal footing "in the eyes of the society." What about in his own eyes? Does the Underground Man perceive himself on an equal level with the officer?
To borrow from Anton Antonitch seemed to me monstrous and shameful. I did not sleep for two or three nights. Indeed, I did not sleep well at that time, I was in a fever; I had a vague sinking at my heart or else a sudden throbbing, throbbing, throbbing! (2.1.27)
Compare the shame the Underground Man feels over borrowing money with the power he later feels over Liza (whom he is paying for sex).
I found two of my old schoolfellows with him. They seemed to be discussing an important matter. All of them took scarcely any notice of my entrance, which was strange, for I had not met them for years. Evidently they looked upon me as something on the level of a common fly. I had not been treated like that even at school, though they all hated me. I knew, of course, that they must despise me now for my lack of success in the service, and for my having let myself sink so low, going about badly dressed and so on – which seemed to them a sign of my incapacity and insignificance. But I had not expected such contempt. Simonov was positively surprised at my turning up. Even in old days he had always seemed surprised at my coming. All this disconcerted me: I sat down, feeling rather miserable, and began listening to what they were saying. (2.3.1)
Actually, these guys hate him because he's a jerk, not because he's poor. The Underground Man simply blames his poverty for outcomes that are really the fault of his character.
I told him at once what my salary was. I turned horribly red.
"It is not very handsome," Zverkov observed majestically
"Yes, you can't afford to dine at cafes on that," Ferfitchkin added insolently.
"To my thinking it's very poor," Trudolyubov observed gravely. (2.4.26-9)
"Insulted? You insulted me? Understand, sir, that you never, under any circumstances, could possibly insult me." (2.4.84)
Zverkov clearly considers himself "above" the Underground Man, just as our narrator had claimed earlier.
It's a different thing. I may degrade and defile myself, but I am not anyone's slave. I come and go, and that's an end of it. I shake it off, and I am a different man. But you are a slave from the start. Yes, a slave! You give up everything, your whole freedom. (2.6.86)
The Underground Man imagines Liza to be a slave because of her social status (as a prostitute) and because of her poverty (she's in debt to her madame). But in fact, he referred to himself as a slave earlier, so it's clear that one's freedom isn't just a result of social status.
"Why, do you suppose he really loves you, that lover of yours? I don't believe it. […] He laughs at you and robs you – that is all his love amounts to! You are lucky if he does not beat you. Very likely he does beat you, too. Ask him, if you have got one, whether he will marry you. He will laugh in your face, if he doesn't spit in it or give you a blow." (2.7.1)
The Underground Man is guilty of the same prejudice against lower classes of which he accused Zverkov; he is not able to see Liza as anything more than a prostitute.
"I am not ashamed of my poverty.... On the contrary, I look with pride on my poverty. I am poor but honourable.... One can be poor and honourable," I muttered. (2.9.5)
Can one be both poor and honorable in Notes from the Underground?
"I told you just now that I was not ashamed of my poverty; so you may as well know that I am ashamed of it; I am more ashamed of it than of anything, more afraid of it than of being found out if I were a thief, because I am as vain as though I had been skinned and the very air blowing on me hurt. Surely by now you must realise that I shall never forgive you for having found me in this wretched dressing-gown." (2.9.28)
The Underground Man's self-professed shame at his poverty raises interesting questions about his value system. If he's such a romantic, shouldn't he take pride in his bohemian or informal lifestyle?