Not releasing an item from your hand, even if it is not needed or is having a negative affect.
Originating from the story of trapping monkeys. This is done by placing a banana behind a device that a monkey can easily get their hand through. While grabbing the fruit they make a fist that wont allow them to pull out and they wont let go of the banana.
Maybe if you let go of your monkey grip on those groceries you could open the door.
I had a monkey grip on the fork and couldn't catch the dropping plate of food.