Emotional damper

Because Primus intended his creations to be able to stop Unicron whenever he would return, each Transformer is a warrior by nature. Even the kindest, most docile among the Cybertronian race have an ability as well as desire for savagery encoded in their programming. Though self-control goes a long way, to keep these feelings more efficiently in check Transformers have emotional dampers installed in their cerebral circuitry.

Fiction

Marvel The Transformers comics

Slag wasn't built with emotional dampers. His general attitude problems aside, this wasn't a real problem except for once every four million years, when he'd go berserk. The last time prior to the launch of the Ark, Slag singlehandedly murdered his entire unit. The Dinobots covered for him back then and took him up in their unit. Whenever Slag's uncontrollable rage manifested itself again, they kept him out of trouble. The 4,000,000 Year Itch!