The sociable Mr. Lockwood, isolated on the moors, wants to think well of his landlord, Mr. Heathcliff. Therefore, contrary to all the evidence before him, he decides at first that Heathcliff is likable. Lockwood is used to the society of polite, genial gentlemen in the south of England and is a polite, genial gentleman (albeit a clueless one) himself; therefore, he projects his own perceptions and experiences onto Heathcliff.
Initially, Mr. Lockwood states that he and Mr. Heathcliff are a "suitable pair" and that he thinks of his landlord as a "capital fellow." He somewhat surprisingly persists in this belief despite noting that he saw Heathcliff's
black eyes withdraw so suspiciously under their brows, as I rode up . . .
Lockwood also states that Mr. Heathcliff invites him in through gritted teeth, as though he is saying "go to Deuce [devil]." Even this greeting, however, does not discourage Lockwood, who decides that he is "interested" in a man even more reserved than himself.
This opening underscores that those who narrate the events of the novel are subjective and not necessarily reliable, because they are influenced by their own particular perceptions of characters and events.