The thing about PVP in WoW is that it's totally true it's rock paper scissors. I learned this from having a bunch of alts.
Just for an example (classes might not be accurate): I'll get raped by a hunter on my rogue. Develop a strong hatred for hunters. So I'll log my mage and destroy all hunters. But by that time I've encountered a ton of warriors that beat my mage, so I now hate warriors. I will log my warlock to destroy all warriors. But then I get beat up by a bunch of druids.
etc, etc, etc