Garrosh Hellscream never got along with his dad. Nope. His dad never thought he was good enough, never thought that anything he ever achieved mattered. Further he was an angry drunk who got angry easily. One day Grom Hellscream got mad.
Garrosh tried to get away, tried to distract his dad with a random brawl (RIP Mana Tide Totem) but nothing worked. Eventually, he was cornered and chose death.