As a long time mmo dps and occasional tank this is one thing that bothers me. Over eager dps that jump in and start laying into a boss or mob before the tank even has time to land an attack. Then continues to burn under the assumption that threat isnt their problem, its the tanks.

As a dps i always do my best to manage my own threat via throttling or reduction tools i have. I also wait for a flash/overpower/unleash before i start in on my own aoes. It helps with positioning and lets the tank breath.

As a tank i dont need a lot of time to get going but if i see a fire2 or dragonfire dive land between my tomahawk/shield lob gcd and the next that will be overpower/flash ill likely stop and let thay dps die to the group they just pulled. If they cant wait the extra 2 seconds for a single tank aoe to hit they can tank it themselves.