With the dramatic rise in robocalls, I find myself constantly being interrupted throughout the day. As a result, I often second guess whether or not it's worth picking up the phone, when incoming calls are from a numbers that aren't in my contacts. But, because some of these calls may represent new customers, I can't afford not to pick up the phone.
I wish there were the equivalent of reCAPTCHA for phone calls. To a human it would be easy to answer a challenge question, but to a machine this would likely present enough friction to filter out the call.
The simplest version of this concept would be to set up a single extension for my cell phone number. The caller would be prompted with an automated audio message describing which extension to enter to not be redirected to voicemail.