Yes and no.
Yes: It's not good for you, plus if you read a bit about the effects caffeine has on the human body (google can help you with that), not to mention in most cases sugar too, you'll see why coffee is bad for you.
No: Some people go their entire lives drinking at least 1 cup a day and they live perfectly fine, long, healthy lives. Drinking a ton of it is very very very bad though, but that same logic applies to almost everything (with the exception of water soluble nutrients).
Back in high school I used to drink a cup of coffee a day. I've been a night person my whole life. No matter what I do, I'm not good at getting up in the morning. I've tried going to sleep at all sorts of hours in an attempt to be able to get up in the morning, but it just doesn't work for me. Anyways, getting a little off track... So in high school I was always tense and irritable. Now in college, I take all night classes, so I don't have to get up in the morning, thus I don't need coffee anymore, and I'm much more happy and relaxed. I personally think if you can find a way to arrange your schedule so that you don't need coffee, go for it, but otherwise, it's not gonna kill you.