(For canon.) The thing about Megamind that is the most true for both his supervillain persona and his real self is that he is incredibly intelligent. A legitimate genius, he is extremely gifted both at thinking on his feet and at coming up with involved plans ahead of time. Another thing that is always true of Megamind is that he has a huge ego -- In reality, it's about his intelligence, and his feelings of being a freak equal it. But when it supervillain mode? He is handsome, genius, talented, and all-around better than you in his mind. This is part of being a supervillain, but also part of compensating for his feelings of being a freakish outcast.