Yes, my dear reader. You heard it right. Your eyes do not deceive you.
Small cup = good, large cup = bad.
You may never thought about it much, but coffee does nave negative effects on your body, other than robbing you of sleep.
Right now you will read an entire freaking paragraph consisting entirely of the bad things coffee can, and likely will, do to you.
Coffee will dehydrate you, remove the much needed life liquid from your system. Logically, that also means you will be forced to visit the "bath" room many times, very often. Kind of inconvenient, isn't it? Coffee will speed up your heartbeat. If your <3 isn't in the mood of beating very fast today thank you very much, you will be doing your <3 a huge disservice :( Coffee will raise your body temperature. If it is hot already, you are fucked. Coffee is very likely to make you want to visit the "powder" room yet again, but for a different reason. If you are really busy at that moment, well, you are kind of royally fucked >:D Coffee will very likely make you sweat if you weren't prior. Name a fool who likes sweating. Chances are, you are not naming yourself. Coffee is among the substances that will stain your teeth like a perfect mixture of glue and ink.
But that is only if you over-consume that dark drink. If you drink a small cup, and none more after that, you are fine.
So yeah, large cups of coffee are only for emergencies, like dealing with depression, or constipation (or both, with former caused by latter). Otherwise, avoid excessive coffee consumption like YouTube cat videos (bad for you in larger than VERY SMALL doses).