I learned massive assertiveness! My first internship was with a politician who was up for election, and the very first day, he told me to buy a cheap, white "Vote for Jay" t-shirt to wear to the various campaign functions. I could see through TWO layers of this shirt! I smiled and said, "I'll buy the t-shirt, but there's no way I could possibly wear it in public - it would just embarrass both of us!" He was stunned - but, making a long story short, he started calling me "the classy broad".
So, while all the other people in the office were wearing cheap t-shirts and slinging spagetti, I got to represent my boss at teas, banquets, and other upscale occasions!
Unfortunately, I also learned the fast way to fan & stuff envelopes...