I don't even answer the phone if the number isn't in my contacts. I can't. I get a few calls per day, it seems. Sometimes it dies down, but then I'll start getting calls again. For some reason, "Google" thinks I own a business and they want to help me out. Also, for the last 3 years I have received a call about my student loans that says I need to "act now" or I will miss my chance.
There has to be a way that service providers can filter out calls that are clearly spoofed. I've heard of people receiving calls from their own telephone number. I've also heard of some random scam where someone calls and hangs up immediately. When the unsuspecting person calls back, they are unknowingly dialing a pay-per-call number and get charged like $20. Literally, the phone call equivalent of the predatory ringtone BS that used to scam people.
I'm on the "Do Not Call" list and have been for 10+ years. It's basically toilet paper at this point because the people calling aren't even in the US and they'll just register another spoof number to try again. Be nice if the FTC would put a little work in and force service providers to figure this out.