I assume that I am not alone in hating it when you get a phone call and it turns out to be someone trying to sell you something. Being fair though, at least it is better then when you get a phone call and there is no one at the other end of the line, now that one really is frustrating.
Anyway, telephone marketing really bugs me. So much so that I opted out using the UK telephone preference service to stop receiving the calls. Mobile phone resellers seem to think they are immune from this and that they can still market to you on your mobile so I still occasionally receive calls trying to get me to upgrade to this tariff or that phone.
I had one of these calls today and managed to confuse the person at the other end of the line to such an extent that they hung up on me. I think this is the first time I have ever had one of these calls and come away feeling happy at the end of it.