On hating a fictional character

I've been thinking recently about hating fictional people.  Generally, of course, characters fall into protagonists and antagonists.  (And bit players, but only seldom would the unnamed shop vendor arouse the kind of passion I'm talking about.)

Generally, if I hate a protagonist, it is for not being what I want him/her to be.  Which might simply mean the author has written a book I do not wish to read.  I might hate a protagonist for being stupid, or annoying, or cloying, or insufficiently feminist, or too superficially feminist.  I think I hated the protagonists of The Lightstone just for being cliche, although I've repressed most of that idiotic book.  I sometimes become irritated at the main characters for the resolution of the plot, if they screw up or otherwise act like idiots. 

Antagonists get more complicated.  I can hate an antagonist in the healthy way, the "how could you do such a horrible thing to this protagonist I like" kind of way, but a deep-down hatred takes a bit more.  Some antagonists are hated for many of the same reasons as protagonists: poor writing, annoying characterization, sheer stupidity.

Excessively incompetent antagonists bring the story down, and often deserve to be hated for that.

More troubling to me are excessively competent antagonists.  David Weber, for example, writes these guys in a way that pushes all my buttons.  They are despicable human beings, careful plotters, often smarter than the protagonists, often blind zealots for a hateful cause, they utterly believe they are doing the right thing... and so they are terrifying.

Stephen King is prone to writing a similar type.  The believable madmen, the unsuspected killers, the solipsists for whom the humanity of anyone else has long vanished. 

It's sometimes enough to encourage me to relish honestly villainous villains.  Villains who rob banks, steal princesses, and plot to carve their names into the moon.

I love reading both Weber and King, but I do often have to break it up with other things.  Because antagonists who I hate so fiercely I could spit, antagonists who make my skin crawl and my bile rise, antagonists who risk having their very books subjected to physical violence, too much of them can, ah, make me rather cynical and angry in day-to-day life.

And when my reading habit starts dragging down the rest of my life, instead of enhancing it, that's when I know I need to take a break.