I 100% agree that it is somewhat unfair, but I don't think it is entirely so. I had this on mind, for example, because a few weeks ago a co-worker had to leave

I 100% agree that it is somewhat unfair, but I don't think it is entirely so. I had this on mind, for example, because a few weeks ago a co-worker had to leave work early one day because she had a terrible migraine that wouldn't go away. She was out of the office for the next few days and even went to a doctor because it just would not subside. What she eventually discovered is that she accidentally bought a decaf coffee. When she switched back to regular, the migraine completely subsided and she has been fine since. Her experience really struck me. It's not really a subject I have ever thought about before, but I wonder how prevalent that level of addiction to caffeine really is.