Bank Details
When I pick the phone up to "BT Support" or "Microsoft Support" telling me they've spotted a problem with my 'whatever' I started telling them I haven't got time for any of this and it would be much quicker if we cut to the chase and I simply provide them with my bank details. Surprise, surprise not one of them has taken me up on my kind offer nor do they have the decency to further progress the "Tech Support" call.