Other Mysteries

As I approach our parked 2010 blue Subaru Forester, I hand the remote and key from my left hand to my right.
 

Hardly thinking or noticing my actions, I insert the metal key into the door lock and twist. I feel the mechanism turn. I pull out the key, open the door, get in, sit down, insert the same key into the ignition, twist, and start the engine.
 

As my right arm returns toward my body, my foot on the brake, the engine running, about the shift from park, I realize something surprising.
 

I unlocked the door with the key!
 

I usually (always, except for this incident) unlock the car with the remote, not the key. 
 

Why?
 

Why did I do it differently?
 

WHY DID I DO THAT?!
I don’t know.
I’m trying to be okay with that.
And, other mysteries.