For reference, I play on a PvP server, though I'm really a PvE player at heart. But my guild prefers PvP servers, so that's where I am.
In my experience, there are two "mindsets" when it comes to player-against-player combat. One mindset is that of chivalrous combat:
The orc warrior steps into the clearing, and sees the human knight. The knight draws his sword and salutes the orc warily. The orc unlimbers her axe and grunts, acknowledging her enemy's bravery. A charge, and there is blood in the snow. A single tear rolls down the face of the victor.
This mindset is old, invoking Arthurian legends, and codes of single combat and dueling. Combat here is consensual for both parties, and they are driven to it by their honor.
The second mindset is that of total war. Here victory means everything, and victory is the goal. Ambush, poisoned knives, the destruction of supply lines, outnumbering your opponents. All of these are acceptable practices. There is no honorable combat, only death and victory. Under this mindset, the entire idea of consensual combat does not even apply.
In my experience, the players who tend towards the first mindset usually prefer PvE servers, while players who tend towards the second mindset prefer PvP servers. But then the chivalrous mindset people see what happens under total war mindset and object to those tactics. And the other side doesn't see why they are objecting. In essence, they are playing different games, and talking past each other.
The thing is that world PvP is not consensual on a PvP server. Or rather, the act of existing is implicit consent.
If you cannot handle that, or you think that is dishonorable or griefing, then you should not roll on a PvP server. It will just lead to frustration. Stay on a PvE server and formally flag when attacking the enemy or do battlegrounds. The act of flagging counts as giving consent on a PvE server, but there is no equivalent action on a PvP server.
For PvP though, the entire mindset is different, and you just have to accept that PvP servers play by "total war" rules. You have to keep your guard up, be alert. It is a tiring playstyle sometimes. (Also, I miss bubble-hearth.)
So why play on a PvP server? Because you get random stories that never happen on a PvE server. The other night I got jumped by a Horde rogue and shaman healer. They killed me pretty quickly. When I got back to my body, the rogue had attacked a druid. But that druid had a friend who the Horde hadn't seen. So I ressed, and jumped into the fight. We killed the shaman, and the rogue vanished and that was the end of the fight.
A short vignette that interrupted my questing, true. But it is something that doesn't really happen on PvE servers.
Finally, from a fairness perspective, the Molten Front is the best place to engage in world PvP. All parties are guaranteed to be level 85. As well, there are usually many people questing, so you can call for help from others of your own faction in the area.