How we cite our quotes:
Heathcliff gradually fell back into the shelter of the bed as I spoke, finally sitting down almost concealed behind it. I guessed, however, by his irregular and intercepted breathing, that he struggled to vanquish an access to violent emotion. (3.74)
Heathcliff yearns to believe in Lockwood's vision of a ghostly Catherine. He is so physically overcome by emotion that he can't even be angry at Lockwood for sleeping in the bed.
"Don't get the expression of a vicious cur that appears to know the kicks it gets are its desert, and yet, hates all the world, as well as the kicker, for what it suffers." (7.42)
Good advice, Nelly, but it's lost on the vengeful Heathcliff. Still, she tries, and this is an important moment. Though Heathcliff has no mentor (see "Character Roles"), Nelly makes an attempt here to provide some useful guidance. (Plus, the dog metaphor is a good one for that house!)
"I never saw Heathcliff last night," answered Catherine, beginning to sob bitterly: "and if you do turn him out of doors, I'll go with him. But, perhaps, you'll never have an opportunity: perhaps, he's gone." Here she burst into uncontrollable grief, and the remainder of her words were inarticulate. (9.145)
Though unwilling to treat him well, Catherine is bereft the very moment Heathcliff departs. She lacks the sort of self-awareness that would lead her to see that much of this mess is her fault.