I almost NEVER answer my door.
I'm serious.
EVERYONE I know has my cell phone number. They all know me well enough to call before stopping by. So if there's a knock at the door it is most likely NOT someone I want to see.
I do peek out and will answer if it's the neighbor, or something obvious like the water company person coming around to tell us they're shutting it off to work on a leak or whatever (but only when I can clearly see the uniform AND the company vehicle).
Otherwise they can pi** off and stand there all day for I care! I have "no trespassing" signs up for a reason.
I know it sounds kind of loony but my home is my sanctuary. I don't like my privacy interrupted at ALL. I will gladly welcome you in and offer you a drink.... just call first.
One morning I woke to the dogs barking like crazy and looked out the window to see a guy in my backyard! Parked next to my house was a big black truck, and I had a six foot wood privacy fence with a gate that he'd entered. The dogs were going nuts but thankfully for him they kept their distance.
I had a wireless doorbell setup on the gate that he'd failed to use. It's hard to explain but the house was basically a "garage apartment" setup that was situated in the "backyard" of another house on a double lot. So the only way to my front door was through the gate and around to my door. So, I had a doorbell (very obvious) for exactly this reason.
I came running out and asked him exactly who the heck he was and what the you-know-what he thought he was doing. Turns out he was from the water company ( I checked the ID) and they wanted me to put some tablet in my toilet and flush it (to change the water color) so they could find their leak.. but this guy was in plain clothes and in his own truck. I reminded him the he's in Texas and if he kept it up he was taking the chance of getting shot and that he should at least let one of the guys in uniform go around door to door if they're going to randomly be entering closed gates! I also told him he should thank his lucky stars my dog didn't bite him. Idiot.
I'm the same way about the house phone though. I don't have an answering machine or voicemail for it and if I don't feel like answering it, I don't. My mom thinks this is crazy, but the way I see it, the phone is for MY convenience, and I refuse to be a slave to it. I do have a cell phone with voicemail and if I can't get to it I will return calls promptly but I don't feel any compulsion to run and answer it either, when I'm otherwise occupied.