Totally agree with this. It's hard to find the right word for what it is. There's a big difference between someone who takes an opposing view and someone who antagonizes.

The word that came to mind when I read the OP was enemy, but our society pressures us to pretend that we don't have enemies (at least not personal ones), even though we often do. It's uncomfortable to think about who our personal enemies are.

I couldn't come up with any enemies.