The Romans named the first month of the year January after their word for door.
This may seem like devoting a major holiday to the pencil, or the teapot. A door is just another household item, right?
Even more extremely, Janua, or door, was intertwined with Janus, really the god of the door. And the god of much more.
Janus was the god of beginnings, and of endings, in time and space. In most cultures, still, you can find an expression of the sort "What starts well, ends well". The Romans took this very seriously, and always celebrated the beginning of anything.
That's because the beginning of one thing often means the end of something else, in the way that a door marks the beginning of one room and the end of the last one. But that ending is not abrupt -- there is always a connection between the two, and if that connection is as important as the two, it makes the whole ensemble stronger.
This understanding was embodied in the representation of Janus, a single god with two faces, one looking back, and one looking forward. A door, a transition, means looking at the whole. It means preserving the best of the past, and working towards good in the future. A useful new year's sentiment.
That's why any transition -- a goal, gate, door, etc.-- must be treated with great care, and, well, positive energy. That's why the Romans, and most other cultures, worshipped transitions. They worshipped connections between the past and the future, between one place and the next. And they built the best doors they could -- and the most wonderful entrance experiences. And the gave special attention to courtyards, balconies, roads, paths, etc. All of these connections enhance, and join 'parts' into a harmonious whole.
Today, ironically, the future has forgotten this aspect of the past.
But, it's a fact of nature that these transitions occur. So we can be quite sure that conciousness, about the importance of doors in creating wholeness, will rise again.