I almost always have one mug of coffee in the morning with my breakfast, but I think it has become more of a habit than a need and I've been thinking about switching to decaf to see if it makes a difference. I have noticed that if I have any more coffee later in the day it makes me more talkative, and if I have too much without eating anything I start to feel like I'm climbing up the walls when in reality I'm sitting still and not doing much and my speech gets very rapid.