We had a pushy salesman who used to call; I had caller ID and knew it was him, but rarely wanted to speak to him (hey, he was pushy). When he called, though, I would answer, because that was my job...answer my phone. One day he called, I answered, there was chatter, he didn't answer my hello so I hung up. He called again, demanding to know why I had hung up "Oh, well, no one answered me so I assumed the line had been dropped". He didn't pull that particular trick again...
O/T, end of story: The salesman got so bad, one day the VP came near my desk and heard me arguing about how I was NOT going to give him employees' personal cell phone numbers while they were on their hard-earned vacations. VP asked me to transfer the line to him. Guy mouthed off to VP. VP banned the guy, his company, and his company's products from our company. All over a $50 disagreement and his pushiness to get it resolved THIS INSTANT.