Why do you read literary biographies and do you get from them what you expected?

There are quite a lot of good biographies of authors (see, for example, the archived post What are some good author biographies?), but what I haven't seen so far is a question about why people read biographies of authors. Is it to discover the person behind the works? To get a better understanding of the works? Hope that the author's life is interesting because his or her books are interesting?

And afterwards, did you get what you expected? Did it change your motivation for reading another biography?

(This is not a question asking for your favourite biographies.)