In my 20s I applied for a job in sales. The interviewer told me I'd be crap. "Fuck you," I thought, "I'll prove you wrong," and got a job with a rival firm. Turns out it wasn't me that was crap but the product. I detested trying to persuade people to buy something they didn't want, didn't need, or couldn't afford.

Some years later I was managing a warehouse. I wasn't a salesman, but I was quite good at persuading customers to take something extra that I knew was good and they would have no trouble selling. I was good at and enjoyed my job, but I also enjoyed the odd bit of selling.

Trust me, I'm a doctor.