Responsibilities include manning and managing the Christmas Lights Untangling stand as well as being knowledgable about the service being offered. The ideal candidate should be able to untangle 3 meters of Christmas lights in under three minutes. They should also be passionate about Christmas. - from A UK Supermarket Is Hiring a Christmas Light Untangler on Atlas Obscura
Of course, the longest string I've ever had to deal with was 100 twinkle lights. I suppose if I had several strings of 100 all tangled together, well....nah, that'll never happen!