Solo content - No need to explain
Died and are running back - No need to wait for that patrol to clear. Run, Nova, Blink, Run, Invis
Having trouble with Pulls (Vortex Pinnicle Lightning thingy) - Mana Shield, Agro, Blink, Dump all threat.
Stuck in a quick heroic with a "gogogogogo" and you need to stop and drink, but you're still in combat? Invis + Drink
I often find that tanks position CC where it will break due to accidental AOE (Paly/DK) - no big deal - I'll just kite the mob away and sheep... Pull big agro, get him ready for sheep, I'm now 100%+++ agro.... Sheep. Then the always helpful Lock hits TAB, DoT's him up and.... Invis.
Doing your Tol Barad Dailies. The collect 9 bones? Well - run to the site - harvest, Mob appears. Nova. Run to the next node. Harvest. Mob appears. Blink. Run to the site - harvest. Mob appears. Use Pet Nova. Run to the node Harvest. Mob appears. You should now have about 4 on you. Invis. You just did 1/2 the daily and didn't waste any time. *I really miss this on my paly*
Collecting cannon balls - Same thing
Most things you worry about never happen anyway.