Coffee
Did you ever wake up in the morning and know that today was going to be a bad day? When I check-in with my husband [who has been working for hours] and he asks me if I've had my coffee yet I know it is going to be a very bad day. My brain just doesn't work right before my morning coffee.
My son inlaw saw an article about heavy coffee drinkers' and non-heavy coffee drinkers' brains in the morning. The heavy coffee drinker's brain looked significantly different than the non-heavy coffee drinker's. Of course after the morning coffee both brains looked the same.
Also, before my morning coffee I am a bear. I wonder if anyone has done a study on morning personality. When coffee drinkers are grouchy in the morning and they have their coffee they are fine. Non-coffee drinkers that are grouchy in the morning are grouchy all day.