The last job I had, the coffee machine had pre-measured foil packets that went one to a coffee run. One day, I drank some coffee, and felt terrible shortly afterwards. I had headaches, heart palpitations, and I felt hyper and exhausted at the same time. The coffee seemed awfully strong, too. Another day, while refilling the coffee for another run, I noticed the used filter was really overloaded with grounds. Later I found out one guy was putting 2-3 packets of coffee per run, because he "wanted it a little stronger." Of course, his desire for stronger coffee without warning anyone could have given me a stroke. For a while, no one knew who this was, until they narrowed it down to one guy and told him to stop. He literally didn't understand why we were upset. "You drink coffee for the caffeine, right?" Luckily, I didn't have to admonish him; someone reported his antics to his manager and the incident was recorded with a sign telling people only one packet per run, and the incident never happened again while I was there.
Today, I forgot this lesson, and drank some coffee at my new workplace. Later today, I found out the reason I felt so terrible was someone in the overnight shift (I get here early) put in 20 scoops (about a cup and a half) for a standard office pot (about 5-6 cups of water). Holy cow. I have decided never to drink coffee here again, or if I have to, never to drink more than half a cup at a time before waiting for several hours just to make sure. Or check the grounds. Something.
Last time I felt this bad was when I ate some FanTek Espresso bean brownies and a Mountain Dew within an hour of each other about 6 years ago.
I feel like a crack whore who just overdosed. I am drinking as much water as I can to thin out the caffeine. I hope I don't have a fucking stroke.