Many of us have discarded a floor lamp that screws together to form a pole and with a light fixture on top. The number one reason is because the pole fails to maintain a tight grip and begins to lean to one side. The lamp leans because the threading has become worn and stripped.
I myself have personally thrown out several floor lamps because of this issue. I was frustrated at how much money I was spending on replacing floor lamps. So early one evening I dismantled my leaning floor lamp and forced myself to think of a solution. After a couple of hours, I figured out the best way to fix this issue and have my floor lamp looking straight again.