Wiggal, do you know the definition of 'a door' ? The definition of 'a door' is 'something which a dog always thinks it's on the wrong side of'.
Some of them love playing this game.
One of mine is currently doing this inside the house.She sniffs at the drawing room door and paws at it. So I get up and open it for her. She then sticks her nose into the hallway, may or may not take one step outside, and comes straight back in again. I think she's doing it on purpose, because she thinks I look too comfortable! And, no, I'm not leaving the door open because a) she then wouldn't 'want ' to go out and this would spoil her 'game' b) there'd be a draught. I expect that were we in the hallway she'd be doing the same the other way round.
You can't win!