Witnessed at holding point recently. "So and so are you ready for immediate?" Affirm is response and cleared for immediate takeoff. Puts the power up and looks to be in position to do a nice rolling start and then proceeds to SQUARE OFF the line up taking at least 20 seconds. International told to go round. ATC says thanks for immediate takeoff and a happy "your welcome" was response. Not a clue. If we want better separation standards we all need to play the game.