Man called, asked for my boss, I could hear lots of background noise in the back round.  He asked for David, rather than Dave. So I knew instantly it was a sales call.  I told him he wasn't in,  I could take a message, he asked very rudely "When will he be in?". I said I didn't know but I would be happy to take a message.  He hung up.  Keeping this number by my phone where I put other numbers that are unwanted sales calls.