Okay, let me add another perspective to this side of sales. The one's who cold call for common, everyday things are telemarketers. Easy to deal with...just hang up. But, I was in a unique position for a few years and did quite well: Diagnostic hardware and software. Developed a stadium full of technicians, computer dweebs and re-sellers who ALWAYS took my call. Back in the days when these guys had to deal with things like IRQ/DMA conflicts in a motherboard (which amounts to having to unravel a problem that equates to 18 to the 18th power...manually)...I had the answers. We could pre-sell diagnostic hardware...still in production...6 months in advance. I had a blast with my customers. I trained them how to be good customers and tell me instantly, if they weren't in a buying mood. I haven't even tapped the great stories that came out of that period of my life...
