A colleague regularly leaves her glasses on her desk when she goes to the toilet. Today, we grabbed them and applied a layer of transparent tape on one of the two lenses. We did it clean, to conceal it nicely. When she came back, she put her glasses on, but something felt wrong. She rubbed her eye, then her glasses with her shirt, but it was still wrong. The scene lasted for 3 long minutes, it was very difficult not to laugh!