You understand it, it is normal, but it just makes you want to scream expletives. Here is one: Windy days in late fall. When this happens, it is difficult to get the garage door down. You hit the button, a leaf blows into the sensor line of sight, and the door stops and goes back up. Usually, you hit the button again and the door closes. There is a day, every once in a few years, when it is really windy and lots of leaves are coming down. I will have to plug in the leaf blower, get the garage remote out of my car, and hit the down button while trying to keep the sensor path clear. One time it took the four tries with the leaf blower. This always happens when you are in a hurry.