Get a little amusement out of life. If a human thinks he can call you and get you to come, run at him full tilt, and then stop on a dime. If said human turns his back on you, knock him down by jumping on him.

Fences are just a good puzzle for cows. The goal is to escape. The biggest pay off is finding a window open in the human's house (preferably the bedroom). There's nothing like the reaction of a human when they come face to face with an unexpected cow in their home.

Don't ever tell me that cows don't think stuff is funny!