My family and I are fortunate that it's not.

signed,

A b2b salesman

With that said, I try to be as respectful as possible of customers' (or potential customers') time. If someone tells me they're not interested in what I sell, I will flat out ask them if it's ok to call them again later down the road. If they ask me not to, I won't. Also, I'm selling a product that is specific to a pretty specific industry so the people I'm calling all potentially have a need/use for what I sell...I'm not just calling every business out there and harassing them.

But, from a saleman's perspective, try to remember that the guy on the other end of the phone is just a dude, like you, who is just trying to make a living for himself and his family