The problem with coffee, the way I see it, is having at least one everyday. If any of us would only drink a cup once two or three days we would see only its benefits and it wouldn't have any chance of becoming addictive. I was addicted to RebBull and sugar and I get the point of addiction.
You're right, one coffee should be enough and can't cause addiction but after a time I couldn't have had just one coffee, had to have more and more, till I became tolerant and had no effect on me any more.
Red Bull and sugar are even worse! Good thing you used past tense, which means you're not addicted any more. Bloody addictions! Although I should blame myself!