fun fact: the brain can build tolerance for caffeine very fast(days to weeks) to the point that basically all regular caffeine consumers have to have their regular dose of caffeine often at specific time of day just to be just as awake as they would be if they didnt have any caffeine. so caffeine only really helps if you take more than your normal daily dose irregularly(~every 3ish days at most on average)
I cut back from daily energy drinks to daily morning coffee and my effective energy doubled. Then I cut back from daily morning coffee to once a week or less single serving caffeinated drink, and my energy effectively doubled again. It definitely does more harm than good used regularly.
I love coffee. Sometimes when I drink it I'm totally fine. Other times when I drink it it feels like my stomach and insides are exploding and puts me out sick for the whole day. No, it's not lactose intolerance. And it's not fixed with decaf. It's just that my body hates coffee even though I love it. :(
That's a little over-simplified. It blocks the sensation of being tired and also has several significant mental effects (including improved reaction time, wakefulness, and hand-eye coordination), as well as physical effects (including increasing basal metabolic rate and improving athletic performance under both aerobic and anaerobic conditions).
So, is caffeine a wonder drug that fixes sleep deprivation with no negative side effects? No. Is it "way worse than drinking nothing" for people that need to stay awake and pay attention with a less-than-ideal amount of sleep? Absolutely not.
I still say I'm not addicted and I can give up my scalding bean water any time I want. But I don't want, so people should leave me to drink my coffee in peace.