Addon: Recount or Skada

 These addons will document damage/healing/interrupts done (and much more). The main reason I use these is not to judge others, but for personal use. They break down everyone's spells cast and can be used to evaluate your own performance. (Why did I run out of mana on that boss fight? Oh - its because I used 18 flash of lights) (Why is my dps so low? Oh, my dot uptime is only 65%)

http://wow.curse.com/downloads/wow-addons/details/recount.aspx

Breakdown to analyze

Overall DPS