I'll never forget my first business trip. I was 21, a greenbean at a big consulting firm. Before my first trip, the two guys I was traveling with (both seasoned veterans) gave me the rundown on checking bags. Basically, the rule was simple: you check a bag, we kick your ***.

I had always flown before age 21 - I studied abroad and was familiar with a lot of the world's major airports - but business travel was a way different beast. It took me a couple of flights, but I soon became a pro at moving FAST through just about any airport/rental car/cab/hotel situation.