Problem with my amp! no distortion?

Did you hit the 'overdrive' button? Maybe the guy had a pedal hooked up to it. Fender Supersonic has a great versatile sound with two gain stages, for a decent price without getting into full tube stacks. A stack is obviously what you want for that awesome high gain sound. Of course Cube amps have all sorts of cool sounds to mess with. I say take your Johnson Warrior back anyway and get something that really cooks.