Clear things were a fad in the early 1990s, so Pepsi tried its luck with Crystal Pepsi. The drink was caffeine-free, and the idea was that since it's clear, people would equate it with thoughts of purity and healthiness.
It worked quite well out of the gate, and even prompted a response from Coca-Cola. But soon after, consumers shied away from it, and Pepsi was forced to discontinue it in 1993.
Yum! Brands chairman David Novak explained in a 2007 interview with Fast Company, "I still think it's the best idea I ever had, and the worst executed. A lot of times as a leader you think, 'They don't get it; they don't see my vision.' People were saying we should stop and address some issues along the way, and they were right."