We've all been there. You're leaving for work and you hit the button to close your garage door. It starts to go down a few inches, then suddenly reverses. The lights flash on the opener like there's a party you weren't invited to. You try again—same result. What the heck?

Here's the deal—safety is smart, flashing strobe lights and all. Your garage door is the largest moving object in your home and it can do some serious damage to you, your car, your kid, your trash can, or whatever else is underneath it when it closes. To avoid crushing deaths, infrareds became mandatory in 1992 under federal law.

Infrareds act like the bouncer at the club, watching the door and making sure it's safe to close. They're a pair of small boxes mounted a few inches above the floor, making constant eye contact with each other like a couple of co-dependents. If something comes between them or breaks the beam, they tell the opener that it isn't safe to close the door. That might seem silly until you remember that your door can weigh more than two-hundred pounds. You don't want that to come down on top of you, right?

Fortunately—or unfortunately, depending on your perspective—the infrareds are a little over-cautious. They can tell the opener that it isn't safe to close the door for a multitude of reasons. If anything, and I mean anything, obstructs the infrared beam, the door will not close. That could be something as big as a car or as small as a leaf. If you have an antique door from the 1800s, all the rattling during opening and closing can throw the infrareds out of alignment too. If you bump the infrared accidentally with a rake or a trash can, they don't automatically reset themselves and will remain out of alignment until you step in to straighten them out.

Once you've checked the perimeter and you can't find anything blocking your infrareds, it might be time to call in the professionals. However, if you've just gotten home from work or you need to leave, you can override the safety feature by holding down the inside wall button [not the button on your remote]. This tells the opener that you are physically standing there and that it's safe to close the door.