Why bother? Life's too short, just put the fecking phone down! I do. Always.
If they've rung during the racing they get a mini-tirade first.
I've go no patience at all with cold-callers - I think it's the most invasive, impertinent thing to do, to ring a stranger and try to sell them something they've never thought of buying, in their own home. The more patient people are, the more they do it... If everyone just put the phone down it would go away.
If I want to talk to strangers, I go to the pub. if I want to be quietly on my own I stay in and read or watch the telly, and I don't want some eedjit on the phone disturbing my privacy - my friends know I only use the phone to make appointments etc; for everything else I use email. If I want to buy something, I go shopping, or I might use eBay. That's it!
As for call centres - I had a real humdinger with ukonline last week. Spent three long calls trying to get someone who could understand enough English to get a grip on what the problem was - then discovered there was no-one available who knew anything about macs, not even the right terminology to use! - they kept using Windows commands, which don't figure on my system... I confess I did get a little heated 
After a few more irate emails to customer services they sorted out the problem - which was spam corrupting and blocking my mail on the server so I couldn't download anything. So I'd spent c£10 for nothing!! And it was their glitch anyway, for not having an efficient spam-blocking system... Hmmmm... These call centres are just a money-making scam, imo.
