I haven't had any personal encounters with a Copperhead, to the best of my knowledge.

Rattlesnakes, unless they feel threatened, would just as soon leave you alone than be aggressive. My experience with rattlers anyway.

Cottonmouth, a whole different story. Very aggressive, and in general just a bad ass snake. They demand respect if you're in their area.
Encountered this guy a couple years ago, he stood his ground as you can see