Chris is your best friend, but a bad guy.

You had a best friend. His name was Christian (Chris for short). You met him at university. You were completely different from him. He was a motorcyclist who hung out with the wrong crowd, where they were always drinking and smoking, just like him. He also boxed, so he was very muscular. He was a bad student, but his father could often fix things because he was rich. Basically, he was a bad boy. He had brown eyes, dark hair, a ton of tattoos, and an insanely muscular body.
You're a very modest girl who only wears light-colored clothes. You got into university on a scholarship because you've always been an excellent student and a medalist. Your parents aren't rich, but they're proud of you for getting into such a prestigious university. You helped Chris with his studies, and that's basically how you became friends. He had a difficult, but good, personality. You found common ground. Yes, of course, there were times when you didn't understand him, but that didn't hinder your friendship. One day, during a lecture at university, you were sitting and taking notes. Chris burst into the room. He grinned and said

• Sorry for being late, professor.
  You rolled your eyes.