Remembering mistakes of the not so distant past I was careful to quickly check both strands to make sure they worked. My plan was to double one strand and run it across the white mantle. Using clear packing tape I put the strand on the top edge. The strand turned out to be much longer than I realized so I ran it along the window sill on my big living room wndow, again doubled. As I taped it to the sill was careful to ensure that none of the sticky side of the tape was accidentally exposed. I have 3 cats and only one window sill in the entire house so its common to find at least one sitting on the sill at any given time. I knew that at some point I'd come home to find tape stuck to someone's butt and Christmas lights strewn all over the house.
After carefully taping all of the lights I gleefully plugged them in. Only half the strand was lit. Crap. I checked the other strand again and confirmed they all worked. So I began pulling off the tape and coiling up the non-functioning lights. After removing half the lights they suddenly turned back on. Crap - again. I checked for loose bulbs or a loose connection but the lights stayed on. The aforementioned cats were of course "helping" me during this entire process.
Success! The lights are up, they're all lit, and only one cat is walking around with tape stuck to his butt. Apparently someone wanted to play with the wad of tape I'd thrown into the trash from the first go-around with the lights. No one admitted to raiding the trash and the cat with the tape only knocked a few things over running in circles to catch the tape. I rescued him.
So you're probably wondering why I believe that Christmas lights will ruin more homes and marriages than any other cause, in the U.S. Think about it. Every Christmas for 22 years I watched my dad put up the tree, string the lights, then discover they wouldn't work. He'd spend an hour or more just trying to get them to work. My mom would watch, while I danced around so excited to put the first ornaments up.
I spent the next 25 years arguing with my husband over the merits of trying out the lights first, then his desire to spend hours trying to fix the strand. Many years we'd go buy another set because I refused to wait days for the lights. The Christmas after the divorce I found a box with more than 10 strands of broken lights, packets of replacement bulbs of many different styles, and the light bulb testers he bought every couple of years. I donated the entire box to charity. Now that I think about it, that probably wasn't a very charitable thing to do; right now there is a family somewhere in this city with a couple arguing over the merits of repairing a strand of lights.
All over the country couples are fighting over lights. Save yourself, and your relationship. Throw out those damn lights and buy a new box.
Happy holidays!