Here in my country, mostly here at the south where I live, coffee is a very common drink. It is cultural to drink it, and everywhere you go, there is coffee.  Sometimes, I hear citizens of the US talking about addiction to caffeine, but I rarely see this topic being brought up by other brazilians in day-to-day affairs. It is actually overlooked and coffee is only mostly seen as one of the factors that can lead to pain in the stomach area, not much care being given to associated anxiety, headaches and such things.  I have dealt with patients with addiction to various substances, but I am yet to find someone who is addicted to coffee, aside from minor withdrawal symptons such as headache. To me, it is a "exotic" topic, to the point where I first found out about this, I was wowed, when I was younger I had no clue it could be addictive.

So I wish to ask, why is caffeine bad?

I think it's slightly silly to worry about caffeine addiction. I've been drinking way too much coffee from a pretty young age, and yeah the worst result I've had from skipping a day or two has been mild headache or being a little slower on the uptake than usual.

Obviously it can interfere with sleep rhythms and such, but so can ill-timed pizza or exercise.