It is human nature to follow fads, no matter how strange or cultish they may seem. Anything from Beanie Babies to cupcakes to even tech IPOs fall into this category, but, ConvergEx's Nick Colas asks, why do some of these trends manage to stick around while others die off? We might laugh now at bellbottoms and the so-called “grapefruit diet”, but at one point in time these were both fashionable – and profitable. So what does it take to make a fad last? Colas looks at a number of quirky trends past and present and importantly for market participants, finds lessons that extend directly to investor psychology and discipline. The bottom line is that we are sometimes blind to our own trading (and fashion) mistakes in the moment, but we are not preordained to make the same errors in perpetuity.