Why does Onyxia cast Deep Breath?

Onyxia's Deep Breath attack has been the downfall of many an attempt on the Brood Mother's lair. As guilds put in more time and more attempts towards downing the great dragon, some noticeable patterns emerged. Every one of the following factors have been empirically proven to affect the frequency of Onyxia's Deep Breath:

What Causes Onyxia to Deep Breath More?

 * Raid clumping
 * Not enough DPS
 * Not enough DOTs
 * The group's Raid ID
 * The race of the raid leader
 * The race of the main tank
 * The class of the raid leader
 * The class of the main tank
 * The tone of voice of the raid leader, and whether or not he has techno music playing in the background.
 * Not all odd groups are on the left and/or not all even groups are on the right.
 * People are not DPSing very, very slowly (and by slowly, I mean f#@%ing slow).
 * Someone got kicked/feared into the whelps (for not being where the f#%@ they were supposed to be).
 * The players in the center are standing next to other people.
 * The real-life gender or race of the raid leader or main tank
 * Whether Onyxia's head is currently on display outside of Orgrimmar/Stormwind
 * Whether anyone in your raid has downed Drakkisath within the past 24 hours
 * Whether anyone in your raid has downed Highlord Bolvar Fordragon within the past 24 hours
 * Whether anyone in your raid has the Ashbringer (beware, dual-wielding Ashbringers will actually increase the chance of being Deep Breathed)
 * Whether anyone in your raid has visited this web page in the past 24 hours
 * The number of gnomes present in the raid
 * The number of Twill pieces that your raid leader has in their bag
 * The current time of day or day of the week
 * Whether the main tank is currently wearing pants or not
 * The amount of activity currently occurring in Barrens chat
 * The current DKP total of the members of your raid
 * The number of members of your raid that are named after Naruto or InuYasha characters
 * The number of Onyxia Hide Backpacks currently being worn by raid members
 * The number of Dragonstalker pieces being worn by raid members
 * The number of times that anyone from your guild has died in the Rookery
 * Asthma
 * Acid reflux
 * For each hardcore real-lifeless player in the raid, Onyxia casts Breath five times.
 * The amount of raid members that haven't gone through puberty.