This is a depressing article. I like drinking coffee, and now it turns out that it's making me groggy and un-alert by default.

I think I've noticed this at weekends - I drink lots of coffee at work all week, and then at the weekend I'll maybe desist for a day, and end up not doing anything productive. Then when I have a cup, I am suddenly infused with get up and go. I really need to cut down :-/