I've been through several attitude adjustments concerning telemarketers. When I was in management with a sales organization, I would often try to hire the better telemarketers (if they were local) to come work for me in a more personal type of sales career. At the same time, I'd even offer tips to the less-than-effective telemarketers in order to help them hone their skills. I guess you could say I was young and idealistic during that phase.
I then entered the phase of toying with them. You can read a lot about that on here, as mentioned above. My favorite thing was to use different "voices," and go round and round with them, acting as if I didn't understand what their call was all about. My best ones were the older black man, the angry Yankee, and the Croatian immigrant. I could have my daughter in stitches when she'd sense the beginning of a long session with a telemarketer. Sometimes I'd even tell her to pick up another phone and listen to both sides of the conversation.
I outgrew that phase as well. Now I'm just rude and either begin cursing or, if I'm not alone in the room, I just hang up loudly. Here is why I lost my patience with trying to help or toy with them:
There are thousands of us out here who use the phone to do business with our clients. We have to call those folks at odd hours in order to get them on the phone. They know who we are when we call, but you can tell, year by year, how their patience with these phone calls is wearing thin. Every time a telemarketer calls one of my clients and pisses him or her off, it makes my job that much harder.