The sheer difficulty of trying to do it on your own, Good Will Hunting-style.

From a recent interview Vice Magazine did with Harold Bloom:

VICE: If a person wants to seriously approach literature on their own, outside of academia, it’s very difficult.

BLOOM: Without a real teacher, an authentic teacher, a real mentor, it’s very difficult for anyone to get started.

This was certainly the case for me. I trace it back to two teachers, actually. I was always a big reader, but the first taught me to tackle serious twentieth-century books like Joyce and Borges. The second taught me the importance of the classics and the Renaissance, especially Marlowe and Shakespeare. Somehow I wound up specializing in eighteenth-century literature.