There are many iconic doors in movies
Shining, after all, would not have been as memorable if Jack Nicholson had peeked through a curtain. Or Dorothy? As she opened the door, the world changed from black and white to color! And of course, without the doors of Durin, Gandalf and his friends would have just been able to walk into Moria straight away. Not that this particular door worked out THAT great.
Doors. Gotta love them.