I'm confused about coffee

If you are addicted to caffeine then quitting it will give you a migraine starting 1-3 days after you quit. The migraine will be gone in a day or two, or if you take another hit of caffeine. So yes, it is addictive. Caffeine withdrawal is the most common cause of headaches for people who are hospitalized; doctors forget to write orders to give them a caffeine fix as part of their hospital diet. It is also an ingredient in many over-the-counter "headache"-advertised pain-relievers.

Caffeine works by occupying sites of neurotransmitters that signal sleep (among others). If you take it within 8-12 hours of bedtime it *will* interfere with your sleep pattern. It may or may not make you feel more wakeful; but it will prevent you from sleeping. If you've ever been tired and "trying to sleep" but can't, you may have been suffering from residual caffeine you consumed earlier in the day.

Coffee and tea also contain tannins--acidic yet bitter compounds plants produce to deter insects (apparently with only marginal effect, but anyway). Tannins can irritate your stomach lining. They are, after all, what people used to use to "tan" hides into leather. Adding fat (actual cream, or non-skim milk) to your coffee or tea binds up the active sites on the tannins with the fat molecules, rendering them less irritating to the stomach.

Like anything else, use coffee and tea in moderation.

Pro-tip: baking soda removes tannin stains from cups and teeth. Try it!

the truth is that it's delicious and keeps me from being stabby in the morning.

This.