I'm terrible at coming up with a good antagonist.
It's not that I can't make a bad guy. That's easy enough. Put a mustache or black hat on them and BAM, you've got yourself a villain. My failing comes in not making realistic or compelling antagonists with which to harass and haunt my heroes.
I'm reading an excellent book on writing called Deepening Fiction, and it suggests that the best characters in any story share a deep and meaningful relationship. The villain and the hero are intertwined; they have to be. If there is no conflict or pull on an emotional level, the reader has lost a valuable level of interest.
Now, this isn't to say that you should always make your villains somehow related to the main character. But there needs to be a relationship. Think about Frodo and Sauron of "The Lord of the Rings." Sauron is never actually IN the books. He is an ever present force that exists in a tower in spirit form, a looming threat that could congeal and destroy all of Middle Earth. Frodo and Sauron never meet directly, but they share a ring. A piece of jewelry that carries the darkest, most evil power in existence.
Harry Potter and Voldemort were bound by a prophecy, but even more so by the violent act that scarred the "boy who lived."
You can go a more direct route, such as Luke Skywalker and Darth Vader, but often the less intimate the relationship, the more powerful the antagonization.
And remember, there are three basic types of conflict to fall back on: Man VS Man, Man VS Environment, Man VS Himself.
What are some great relationships in movies, books and films that you enjoyed? Comment and post below and share your opinions.