When a cat tries to open a door at night, it could mean that they are curious, seeking attention, or trying to explore their surroundings. Cats are known to be active at night and may be trying to access a different room or area in the house.
with a key
what does you left your barn door open mean
"... it TRIES to unlock..." is the 'key' here...Since we know a sliding door will not open until it is unlocked, I would investigate the locking mechanism.See "Related Questions" below for some specifics - note the one about the door ajar problem has lots of information about the door lock actuators too.
Most likely the door has sagged and the lock is not catching in the strike plate.
if you mean open door policy, it means everything above board and honesty
"Shut your mouth and open the door." (Shut up and open the door!)
the door creeks open and the keys fall
You (plural) open the door.
It may mean that it could be terminated at any time by closing the door. It may mean also that love could be practiced with different partners (and not only restricted to one partner) as the door is open for all.
it mean the grim reeper did it
No, but it may ruin the food! Depending on how wide the door was left open, it will just take some time for the fridge to reach its correct temperature again.
because cold air gets in