I had always drank a great deal of coffee. I joke that my grandfather would put it in my spill-proof cups as a toddler. At this point, I don't know if that's true or not, but even when I was 6 or so, I'd order coffee at breakfast. My household was definitely one that went through multiple pots on a daily basis.
When I started playing guitar in 5th grade, I really looked up to my teacher and we bonded over drinking espresso drinks from a small bookstore/coffee shop down the street which is sadly no longer there. I got my first espresso machine for Christmas in 6th or 7th grade. Fast forward to me working in startups, and I was at betahouse in Cambridge making dozens of shots a day with our Silva espresso machine trying to learn to get them perfect- drinking all the failures to force myself to learn.
I was probably drinking at least 12 caffeinated drinks per day. I had terrible headaches without caffeine. Having it didn't help anything much, but it was a life-long habit.
Then, when I was working at gamerDNA in Cambridge, I had just left a meeting at Andala (where I had an espresso naturally) headed back to the office to provide moral support for a code-deploy night (I wasn't coding at this point much myself).
And while crossing Mass Ave my heart suddenly started beating fast- really fast. I went to the office and kept sitting down to check my pulse. It seemed wrong. 180bpm? I must be counting in triple. I had a few others in the office try the same. It was weird. I didn't feel right. I went homeward, stopping at the neighbor's place next door. After an hour of this I had them take me to the hospital. My heart had been beating at 180-200bpm for over an hour it seemed. My counts weren't wrong.
It appeared that I had triggered some heart arrhythmia. It stopped on its own a few hours later, but the long term diagnosis was to avoid all caffeine and stimulants. The doctors were utterly shocked when they found out how many drinks I had that day (around 14 so far).
The next week was terrible, between beta-blockers they put me on and no caffeine.
I missed caffeine. But having even a small amount would send me into panic attacks and arrhythmias (neither was fun). Finally, about a year or so ago I had a heart abalation which fixed my issue there completely. No medicine needed. And no ban on caffeine.
Now I'm back to drinking coffee- albiet not as much as before (now 2-3 drinks/day is totally enough). I've also been able to get on adderall which is a magic wonder-drug for me. If I had this in college and high school, I would have been 10x more productive and a straight A student.