With email, I get to decide if I want to read it or not. With the phone I don't get to decide if I want to let it ring or not.

The real issue is that phones were ever allowed to ring in the first place. They should all just leave a message which should then be stored until a I chose to listen to it. Then in the future, calls from that number could be allowed.

In addition the phone company could allow you to preunblock certain numbers, such as those from your schools and hospitals.