When Yulik began her training for Starfleet, she earned herself a reputation for being highly aggressive and competitive among her peers. She was eager for success, and that fire is what drove her service in Starfleet to be of excellence.  In her time on the Sulu, she has grown comfortable in her position and confident in her abilities, considerably taming her anger.  She continues to behave overly aggressively and competitively, though, for fear of losing her edge.