When I go into the milking barn, I have to lock the door behind me or Bonnie opens the door and enters before I'm ready. It isn't that she is anxious to be milked. No, she just happens to know that she is going to get some sweet feed when she goes to the stanchion. Food is her primary motivator in life. In other words, she fits right in with us.
First you will see her opening the door. Then after I lock the door, she keeps on trying.