I dont answer the door, someone is there now, knock knock knocking, bless 'um 
My family walk in, and call first, friends all text first. The postie leaves everything in the porch, or shouts
Im not expecting anyone so why should i bother? Its a knock at the door not a summons!
I never answer my phone, unless its my DH, Dsis, Dniece or Ddad. Id rather hear the message and reply at my leisure...if at all.
Unlike posters who dont for mental health reasons (although i do suffer with these and it is sometimes the reason) I am a LAZY COW :)