I used to make purposely crazy drawings in psychology so that if/when I was caught, she'd think I was insane. Two years later, she wouldn't let me near her kids. It was an experiment that was VERY successful!
I was so good in geometry that my teacher would tell everyone to pay attention and no drawing, etc. But he'd come over to me and ask what I was drawing and say how nice it was. I just laughed inside. I usually finished the assignment before it was done being handed out.