Hello reader(s)! Fun fact, the double door was invented in 1645 by Thermopoly F. Doubledoor of Manchester, England. He realized the simple fact that if one door as an entrance/exit to a building was good, then TWO would be better. Two, not one, but TWO streams of people could enter and exit a building at the same time.
Mind. Blown.
Here's a fun picture of this amazing invention, using space age steel and glass.

There is only one teensy-smeensy-bleensy-queensy-fleentzy little cock-crushing problem.
IF ONE OF THE DOORS IS KEPT LOCKED IT DEFEATS THE PURPOSE OF HAVING DOUBLE DOORS FOR THE LOVE OF [DEITY, OR NOT, WHATEVER]!!!!!
This happens with startling regularity at: Starbucks, Starbucks, and there's this coffee place that serves coffee called Starbucks.
Why? Why is only one of the two doors unlocked? Am I on camera lurching to a stop against the unexpectedly locked door? Do sadists work there who secretly wish hot coffee spilled on people?
The world may never know. However, if you hear of a rash of doors being crushed and destroyed by some masked, anger-soaked, vengeful living god of destruction (pssssst! That's me! Don't tell!), now you know why.