I drank one to two pots of espresso every morning before school the second half of my sophomore year of highschool (I only got the machine halfway through the year), and well into my junior year. After that it became less regular, since it was such a vile brew. Hence the addiction to caffeine I've had ever since. In college I drank either an energy drink from the machines in the student lounge, or coffee from the vending machine in the same.
Also, salt, as odd as it may sound, is perfect for coffee. The trick is figuring out just how much to add to cut the bitterness without any salty taste. I never did get it right with normal table salt, it either did nothing or tasted like... well, like salty coffee. About an eighth of a teaspoon (or is a quarter? I forget what it came to when I measured it out...) of some fancy sea salt shit that happened to be by my stove when I was making coffee once does the trick pretty well.
I got the idea from my grandparents, who mentioned it when I said I had once been so desperate for caffeine that I boiled coffee grounds in a pot (since I lacked a working machine at the time; the espresso machine having worn out through a distinct lack of cleaning and fell victim to a roach infestation). My grandmother said something about that being (part of) a traditional way of making coffee in sweden: boil or heat coffee grounds, throw in egg shells to filter out the grounds (somehow? I don't really understand how that would work, perhaps the grounds stick to them?), and then add salt to cut the wretched flavor you get from boiling the grounds directly.