Back in the mid 90s I was working for a small games company. Being a semi-senior member of a small team I was often the person others turned to with questions. Most of the time I was happy to help, but occasionally I just needed to get stuff done. One particular day I had to get a demo finished for the following morning, and the interruptions were coming thick and fast. I ended up taping a big “Fuck off, I’m busy” sign to the back of my chair. Which worked really well until about half six in the evening when I got a friendly tap on my shoulder. “That’s not very nice,” said the cleaner with a big grin on her face.