Given my experience with robocall and stuff, I _do_ want to be unfriendly. I hate to guts that a lot of people assume that they can interrupt you at any given moment. One guy called me when I was driving and wasn't having any of that, kept on complaining that I didn't pick up.
My current plan right now is to have a landline number from my internet provider (that's SIP essentially). Whenever anybody requires a phone number give that.
Now, there will be an voice mail device on my side with message: "Hello, you've reached p2t2p and his wife. We _DO_ _NOT_ appreciate your call. If you think your message is important, leave a message and we maybe, just maybe call you back. Otherwise, use email please".
And that is not even for bloody robocalls. Every single bloody prick think they are important enough to steal my time. Hey, I wrote you an email so respond to email, dumbass, don't call me. There were one windows installation company that stopped interacting with as soon as I told them that I won't pick up the phone and asked them to use email.
I guess the ultimate solution is to have my iPhone in permanent "contacts only" mode.
(Yes, I know, a significant portion of my email ends up in their hands anyway.)
My mobile carrier puts "scam likely" on calls that its algorithms have determined are likely spam, I wish there was an android option to just not ring the phone if that was the caller ID name.
Maybe after a few popular apps do that, the phone companies will start to fear losing relevance and finally take effective action against phone spam.
It only bit me once in several years - I was expecting a call-back from a doctor and they weren't in my contacts. Missed their call, which caused a several hour delay and some annoyance (thankfully not for something critical).