When Can You Say You Don't Like an Author?

Recently I was talking to someone and they said that they "don't like Shakespeare". I basically proceeded to make this face.

I know that person tends to not like things with sad endings, so I was like, "Ok, I get why you don't like the tragedies. But the rest?? How can you say you "don't like Shakespeare"?!"

They said they thought they'd read eight plays, including Hamlet, Romeo and Juliet, and The Merchant of Venice, but they didn't really like any of them.

Later, while I was musing over this conversation, still bewildered by how someone could dislike Hamlet (HAMLET!!); I started thinking, well, when is it ok to say you don't like an author? How much of an author's oeuvre do you need to read before you can make such a judgment?

If you've only read eight of Shakespeare's 40ish plays, can you make such a sweeping statement about liking or disliking him? That's about 20%, which doesn't seem like enough to make an accurate decision; but I've read less of other authors, and decided that I didn't like them. 

For example: David Baldacci has written 27 books. I read one, and thought it was terrible. So I'm judging David Baldacci based on less than 3% of his writing. (You could argue that all of his books are thrillers, so reading one thriller gives you a pretty good idea of what the rest will be like, and Shakespeare wrote across many genres, but still.)

At some point we all have to quit reading certain authors, or decide that we prefer other authors, because we can't read everything. I guess it's fair enough to say that you don't like Shakespeare if you've read* several of his plays and didn't like them. 

But maybe I need to give David Baldacci another chance? 

When would YOU say you don't like an author?

*Although, my quibble is that his plays weren't meant to be read. They were meant to be seen! I feel like you can't see a theatrical or movie production of Shakespeare without realizing the genius.