We’ve all done it – knowing full well we shouldn’t. Caught off guard coming out of the shower or going into a meeting, returning from the supermarket with an armful of groceries, or preparing dinner for family and friends, we’ve answered that call from “No caller ID” or prefixed with the number “3”.

Yes, it could be the boss checking in from abroad, an important client or even a long-lost relative – but then the inevitable blitzkrieg of babble ensues from the telemarketer on the other end of the line.

Worse still, how many of us, drilled in the art of cold-call recognition, have barked a gruff “Hello” at a suspected telemarketer only to find that, to our embarrassment, it’s a genuine call from a colleague or client?

When the telemarketer does come calling, it’s wise to have a strategy in place for dealing with this insidious nuisance. A quick survey of family and friends reveals some of the best.

One says she waits for the caller to ask, “Do you speak Cantonese?”, then swears in Cantonese and hangs up. Another reverses prank-call psychology and does some heavy breathing of her own.

Cold calls are not only a nuisance, they’re also ineffective

Woe betide anyone who dares to call my mother without good reason. She’s in the habit of keeping a whistle by the phone, and a quick blast is enough to see off any unsuspecting telemarketer.

One friend tells me he puts his phone on the desk, leaving the salesperson to a one-sided conversation until they eventually realise they’re talking to thin air. His logic? If they’re determined to waste my time, then I’ll waste theirs.

More Hong Kong people receive cold calls, but many hang up without listening to the message, according to survey

One says she contrives to burst into tears while another likes to put her two-year-old on to give the caller an early Christmas wish list. And an acquaintance with musical leanings has taken to singing The Sound of Music, sotto voce.

Stop the cold calls: Hong Kong’s privacy watchdog demands stricter rules on telemarketing

There was a time when “2” numbers were safe, but now they, too, are transforming into telephone triffids. What marketing genius dreamed up this approach of courting potential customers with the verbal equivalent of a paintball attack? Does anyone buy it – either literally or figuratively?