1. I'm a Balance wizard and, therefore, don't have the tools available that "PvP" schools like Fire and Myth do.
2. My power-pip chance is so high that it costs me 6 pips to shatter, 12 to quake... Not exactly efficient.
3. I don't have a mastery amulet~ not because I can't buy one, but because I consider it an exploit. Players who don't have money won't stand a chance at high-level PvP... that, and these magical necklace thingies are practically a requirement for Balance to PvP at all (since we rely heavily on off-school spells to keep our strategies intact).
4. No level restrictions on treasure cards. I want to try PvP with my noob Fire wizard (she's level 15), but am too scared that her opponent will be a level 6 spamming Earthquakes, or something...
5. Because most of the PvPers I've met are a bunch of entitled whiners who care more about their own needs than those of the w101 community as a whole.
(General PvP attitude: "OMG, Storm is soooo overpowered! A Life wizard defeated me with Guardian Spirit, so let's nerf healing! Mana Burn stole my pips and gave me a free cast! Let's nerf that, too... And, while we're at it, let's ban all dispels, shields, and blades from the arena! That way, I don't have to strategize and can spend more time whining!")
6. There are too many exploits~ those who play fair won't stand a fighting chance.
7. My only incentive to PvP? That gorgeous Dragonspyre trophy. It would look so perfect in my Grand Fortress, but alas! It's not to be. :(
8. I suck at (and intensely dislike) math~ always have, and likely always will.
9. Now that I think of it, I also just plain suck at PvP.
(I've never actually 1v1ed, but did try team PvP a few times and ended up being the healer AND the tank. My teammates were Fire and Storm, and we faced the immortal trio of Life, Myth, and Ice... needless to say, we got slaughtered, and I haven't been back there since).