A man walked into an insurance office and asked two senior executives for a job. "We're not taking on new staff," they said. "But you can't afford to be without me," insisted the man. "I can sell insurance to anybody, anywhere, anytime." "Okay," they said. "Prove it. There are two prospective clients who have resisted all our attempts to sell them a policy. If you can sell to just one of them, you're hired." The guy was gone for around two hours, but when he returned he handed over two cheques –…