For most people, caffeine use is harmless if and when it is used in moderation. When you consume too much, it places too much stress on the central nervous system. If you have cardiac problems, caffeine can even lead to heart attack or cardiac arrest or even a stroke. So yes.
There are major negative effects to caffeine use. I personally down a lot of Mountain Dew, specifically Diet Mountain Dew, which from my understanding is even worse from me. It's not my only bad habit, but it's one of my bigger ones. I experience the negatives of caffeine when I don't have caffeine. Namely a pounding headache and the inability to feel fully awake.
Caffeine is a very strong substance and has lots of cons that can have effects on your body. Cons such as messing with your eyesight or causing damage to your teeth. These are just some of the symptoms of using to much caffeine especially in coffee. Anything can be overused and caffeine is no different.
Caffeine use prior to working out is very helpful. However, there are negative affects if a person intake caffeine after working out. Meaning it doesn't allow the muscles to start to repair and this slows recovery and adaptation to the working and tearing that go on from resistance and endurance training.