Mr Darcy's question about the reversed situation was... unfortunate, to put it politely. In one phrase, he implied the sisters were penniless, possibly mercenary, and concern is always guaranteed in such cases. The sisters are not precisely penniless, their personalities are ignored (which should have given him a hint on whether they might be mercenary), their status ignored (as a daughter of a gentleman is a fair prospect for a gentleman-like son of a tradesman), and Elizabeth's pertinent remark that there is a huge difference between stating you could not discern the feelings of a virtual stranger and swearing that no feelings exist while you never actually talked to that person, was completely ignored. How convenient. She gave him a clear example why he is arrogant and he compounded that with a seemingly reasonable argument of what would you do in my shoes by ignoring any inconvenient argument and describing a dire situation of a penniless mercenary without factoring any of the actual circumstances in his arguments. Again arrogant, and he smiled throughout it. Too bad Elizabeth's debating skills are not as trained as his and too bad her thoughts are now focused on his feelings. Somebody should have shown him that his arguments had more holes than Swiss cheese.