Likable characters?

Should writers create "likable characters" for their readers? Two novelists, Mohsin Hamid and Zoe Heller, debate this question. Hamid reframes the question, asking:

Perhaps, in the widespread longing for likable characters, there is this: a desire, through fiction, for contact with what we’ve armored ourselves against in the rest of our lives, a desire to be reminded that it’s possible to open our eyes, to see, to recognize our solitude — and at the same time to not be entirely alone.

Heller suggests, however, that the question is an important one that needs to be answered. Although she's not wholly comfortable with the idea that readers need to "like" fictional characters, she concedes that readers do need to care about them:

Other fictional characters may invite or accommodate more complex responses, but most authors aim to engender some species of readerly empathy for their protagonists. It’s not necessary to “like” Hamlet, but if we’re so repelled by his treatment of that sweet girl, Ophelia, that we withdraw all sympathetic interest in his dilemmas, then the play is unlikely to mean much to us.