For people unfamiliar with the term, cold callers are generally people who show up at your door usually wanting to sell you something. When you get an unsolicited visit, what do you do? Have you had any interesting encounters?
These days, I don't bother answering. Nobody but me has any business showing up at my door. But when I lived with my dad, people used to show up every now and then, and my dad would always answer. One time it was the polling organisation Ipsos Mori and they gave everybody who answered their questionnaire a £10 voucher. Another time, my dad wasn't in, so I answered the door and there was this shady looking guy stood there who handed me a note, which basically explained how he was an immigrant who couldn't speak English, and that he was going door-to-door selling his artwork so he could fund school or something. I didn't have any money, so I told him sorry and closed the door. None of his drawings had any prices on them, though. So if he couldn't speak English, I don't know how you were supposed to barter with him. Another time some Mormons showed up, my dad saw them, said "I am a nonbeliever" and shut the door. I was caught by them another time, but didn't have the heart to close the door on them, so I listened to what they said and accepted their book.