Parsers and Problems

[Ronaldus]

That said, while raiding or dungeoning ANYTHING could happen. Know what your skills do and how and when to use them is what is most critical. Using Elusive to move out of an AOE is waste, but what if you were stunned or slowed? Then it's a DPS gain to not die. But what could you have done to avoid the stun? OR oops the tank died, do I want to elusive jump? Probably not. I probably want to hit all my defensives and then sprint to kite the mobs away until the tank returns. Once the tank returns maybe then elusive in order to help restablish agro.

tl:dr
agro is irrelevant to dps (abilities reduce agro, classes generate agro at different rates, people may die, etc etc etc)
dps is irrelevant to good playing ability
good playing ability includes knowing when and how to use ALL of your abilities in various situations

[Ronaldus]

Also, parsers are used for more than just calculating DPS. They're also used to look at who was using what buffs when. Like, if your Dragoon buddy keeps dieing to the missles on A1S, before you go screaming at the healers it's nice to know, did he have blood for blood up? did he use any defensives (Foresite, Keen Flurry, Second Wind)? Or what if no one caught who had that lightning debuff on T10 and wiped the raid? Parsers are invaluable. And using parsers doesn't mean you have to be a jerk about it either.