School’s not for everyone, right? Sure, some folk are suited to hitting the books, but others are more into... well, hitting other things.
Like that jerk who spilled your drink and that robot that looked at you funny. Duke flunked his military training too, so he now hops from planet to planet in search of another way to address his daddy issues, helping himself to whatever he happens to find on the way. What he lacks in purpose he makes up for in optimism and his faith in other people - even those that want to kill him. Hang on, is Duke an idiot?