Yeah for sure! Caffeine is like a drug anyway, so it's a bit like when you get high and then you come down and feel angry and irritated very easily. But because coffee or caffeine doesn't get you that high then the come down isn't as bad a an illegal drug for example...
Some people also get angry when they are used to having coffee but don't have it, like my dad has a coffee in the morning usually, but if he doesn't have time it makes him in a bad mood
