God I hate people like you on my tank. Yes I appreciate tricks of the trade, but I still want to pull. You know why? Because maybe I have a drink in my hand, or the phone rang, or the doorbell rang, or my dog was scratching on the dog asking to be let out, or any of the countless other things that pop up in real life that require my attention for 30 seconds to a minute. Your god damn ADD is pissing me off in real life. It has nothing to do with tanking or having trouble picking up mobs. It's the fact that you are pulling when I'm not ready for any number of reasons, and it makes life more difficult then it needs to be.
Let the tank pull. It's not your job to set the pace of the dungeon as DPS, although you can certainly influence how fast things die.