Very good and frank post as always 
My favorites are the cold calls as i tend to get to the phone first.
Can i speak to the person who looks after xyz - usual response err that'll be me then (irrespective of whether it is or not)
Recent call went something like
"Oh hi my name is Donut from BT- who is responsible for your phones"
"That will be me" i say in a reserved tone
"i'm calling from BT - do you have a BT line?"
"If you really were from BT you'd surely know?" -( heckles are rising)
"Ah well i'm not actually calling from BT im ringing on behalf of them - so how much do you pay for your line rental"
"Again - if you are ringing on behalf of them, you would know" (quite bored tone comes out)
"Well we can't actually see how much you pay as we don't have that system - we are in your area tomorrow can we call in and see you to discuss your phone and show you how much we can save you?"
"Not interested thanks" (point of putting phone down)
"oh so your not interested in saving money for your business?"
"No i'm not " -( ok by now im really peeved - if he carries on theres gona be blood shed!)
Click at the other end - awww what a shame i was looking forward to a chat
Im all for companies calling trying to sell stuff but dont sell at me, try talking to me and take a hint if im not really engaging in the call !!