If you drink coffee every day and one day you can't, do you get a headache?
I don't know. Maybe I need to find out. I used to have a job that was the most repetitive job (mentally) and coffee just began as a means to an end. Later, I've found it's more an enjoyable thing. But probably I overindulge and need to detox.
Probably around four or five. I wouldn't say grumpy but definitely susceptible to irritability if I've got things I want to focus on and get on with. It's always more appreciable after a long wait.
Something I want to get into more is different coffee styles. I like Vietnamese.