I believe that in an ideal doggy world there would be no such thing as doors. The doggies would be able to wander from room to room and go in and out of the house without assistance.
My other doggies would lie down on the opposite side of the door and wait for me to return. Lizzie looks longingly at a door after one of us has left through it. Looking at her I feel that she's trying to figure out why her people disappear through these strange openings. Instead of looking frustrated by the barrier she looks terribly sad. When I left for a few minutes earlier this evening she timidly approached the door with me. When I said "stay" she looked so downtrodden. (Major guilt trip.) Sheesh, my husband was home, and I WAS coming back in a few minutes. It didn't matter, she was majorly bummed.
She's lying on the bed next to me: sound asleep with toes twitching. Maybe she's dreaming about a home without doors. Happy dreams, Lizzie!