For some people it happens when they are young, slinging lemonade or negotiating with siblings. For others it's a revelation later that there's bread out there if you care to chase it.
One of the moments for me was when I was pretty young. My mom used to bring me to the car dealership when she bought a new car and one year I negotiated a price lower than she was prepared to pay. The guy told me I should be a lawyer -- I chose sales.
What's your story?