Related post: Everyday belief in diminishing returns is subject to diminishing returns Growing up as a first-generation American, and generally considered the "smart" one of the family, I started drinking instant coffee when I was 12 to keep awake during homeroom. My usual sleep window now is between 11 pm to 7 am; back then it was more around 1 am to 9; the time I had to wake up to get to school was 5. It was a necessary evil at the time. One cup in the morning became two, and then four; when I got home, I realized I was suddenly feeling groggy, so I started drinking 1 -> 2 -> 4 once I got back as well. This unsurprisingly made my actual lack of sleep all the worse. I think in the back of my mind, I understood intellectually that this was a Very Bad Idea. Even compared to the average person, I function really poorly when I'm tired relative to when I'm awake. But I also have an extremist bent to my personality; I felt throughout high school and much of college that if I were going to quit coffee, I wanted to do it cold turkey. I would be strong and bear the pain. The big problem with this is that I Pavloved myself into loving the taste of coffee too much to ever have success with this after high school. (Thank Christ 12 year old me understood this was a possibility, and reflexively refused to drink anything but black coffee -- otherwise I would be several pounds heavier.) There are downsides to drinking coffee of any variety, decaf or not. It gradually stains your teeth. Last year I paid a few hundred dollars to get my teeth whitened because frankly I found them yellowed enough to be off-putting when I looked at myself in the mirror, especially with a pale sunscreen tint on the surrounding skin creating a contrast. But let's be honest with ourselves: Slightly stained teeth are much, much less annoying than eternal nights spent in half-sleep. About 6 weeks ago, undergraduate winter break began here at Northwestern. I didn't have much to do, so I figured this w