Do you need caffeine to get through your day? I’ve experienced every over-the-counter wakefulness supplement produced before 2007 (when I smartened up) and can promise you that it all has the same effect: A brief period of increased alertness is followed by a dramatic increase in lethargy (a crash) or anxiety and fidgeting. Consume enough caffeine combined with whatever jungle juice is in vogue and you’ll eventually turn into an over-clocked grouch.