holy, that's quite a lot. Even the strongest energy drink I've ever seen sold retail in the US had "only" 300mg of caffeine. And it came with plenty of signage

holy, that's quite a lot. Even the strongest energy drink I've ever seen sold retail in the US had "only" 300mg of caffeine. And it came with plenty of signage on the packaging, indicating very prominently how high the caffeine levels were. I usually drink 200mg a day total (sometimes, but rarely, crossing into the 300mg territory), and you were totally correct, there is absolutely no way to not notice when that 300mg comes from a single drink. In no world would I expect a random caffeinated drink at Panera to go above that.