Well, the absence of caffeine was a side effect, not a requirement. While my favorite caffeine comes in brown, I could have found technicolor mountain dew variants, or faced the wrongness of caffeinated water- but I just don't really like them too much. All in all the absence of caffeine didn't really effect me too much. At least I don't think it did. When I got grumpy, it was more because of lack of starchy snacks than lack of caffeine, I think.