I barely remember my mom's cat, Speedy, from when I was very little, but mom tells me all the time that Speedy was the one who taught me to open doors! It only worked with doors that opened out, though. Mom says that he would sit down with one side against the door, then jump at the knob from the side. His paws would catch the knob, turning it as he slid down the door, and his weight would nudge the door open. Then he and I would make our grand escape together.