All drama comes from conflict. You want something and something else is in your way and suddenly there’s the conflict and there’s the start of your play.

You are in a room with a door. But the door is locked. Or better, there is no door. “Where is the door? I wanna get outa here!” Because there’s a tiger in the room with you. Or there is a murderer in the room, standing between you and the door. Or the room is pitch black. And you can’t see the door. And there might be a murderer in the room somewhere. Or there is a fire starting to burn in one of the corners of the room. Or a baby is crying on the other side of the locked door. And maybe the tiger is out there, looking at the baby, and all you can do is watch though the little window in the door.

In a farce, the door keeps moving. In a mystery play “Where is the gosh darn door?” In a tragedy or a comedy (which is which depends on how quickly the characters talk) the door might be too small.

By the way, as soon as you open the door and get what you want, the play is over.