when i see a number i don't recognize or can't deal with answering at that moment, which is most of the time, i let the phone ring until the answering machine picks it up.
the door is harder. in fact the other day a state trooper rang my bell which scared the crap out of me. i had to answer it though lol. turns out there was a burglary in the neighborhood, which also scares me.
for me my dogs create a major distraction with the door. i have to focus so much energy on keeping them in the house i forget how much i don't want to answer the door lol. it's also a good excuse why i can't come out or let people in, which is good.