Let me tell you how I got the idea.     

I have this fancy coffee machine where I can select a different kinds of beans. And I like a cup of coffee. So when it’s after lunch, I switch to decaf.   The next morning started with a cup of coffee. I was working and feeling really bad. 

Headache, a foggy feeling, and was grumpy, and it got to a point that I was going to call in sick. And then it hit me; I forgot to switch the coffee machine to normal mode.