You and Roadbuster were recently sent on a mission, and during the mission at that time, Roadbuster was having the time of his life as he shot down any Decepticons on sight as he made charismatic speeches in battle

However after your mission has been accomplished, you are just roaming around the base when you see Roadbuster sitting not with the other group of Autobots, but alone, revealing he's the quietest of the Autobots, growing withdrawn and depressed, and is easily bored. Who knows what he's planning in his thoughts? Maybe to plan another battle or find any random decepticons to destroy.