How many heavy squats have you performed? The one and true way of squatting heavy is with an empty mind. The void knows no fear. Aggressiveness is a reaction brought forth by fear (adrenaline surge).
It's just like when you take a hard hit to the head in a fight, if you let the adrenaline get in your head and become exceedingly aggressive, you will open up like an amateur and take many more hits to the head. The same way, the bar will staple you into the ground if you approach it without an empty mind and let your guard down.
Namaste.