@above^
Well it's true it has side effects like insomnia, nervousness and restlessness, stomach irritation, nausea and vomiting, increased heart rate and respiration, and other side effects.
My main concern is that caffeine is indeed addicting and people can experience withdrawal symptoms. I'm going to copy and paste some information about caffeine addiction below for anyone interested
Studies have demonstrated that people who take in a minimum of 100 mg of caffeine per day (about the amount in one cup of coffee) can acquire a physical dependence that would trigger withdrawal symptoms that include headaches, muscle pain and stiffness, lethargy, nausea, vomiting, depressed mood, and marked irritability.[3] Professor Roland Griffiths, a professor of neurology at Johns Hopkins in Baltimore strongly believes that caffeine withdrawal should be classified as a psychological disorder.[3] His research suggested that withdrawals began within 12–24 hours after stopping caffeine intake and could last as long as nine days.[4] Continued exposure to caffeine will lead the body to create more adenosine receptors in the central nervous system which makes it more sensitive to the effects of adenosine in two ways. Firstly, it will reduce the stimulatory effects of caffeine by increasing tolerance. Secondly, it will increase the withdrawal symptoms of caffeine as the body will be more sensitive to the effects of adenosine once caffeine intake stops. Caffeine tolerance develops very quickly. Tolerance to the sleep disruption effects of caffeine were seen after consumption of 400 mg of caffeine 3 times a day for 7 days, whereas complete tolerance was observed after consumption of 300 mg taken 3 times a day for 18 days.[5]