I thought Bitcoin would become just another FAD or craze or whatever people call it these days. A craze are usually a enthusiasm for a particular activity or object which appears suddenly and achieves widespread but short-lived popularity. Source : Oxford

So, I did not invest in it at the start, because I thought it was "Nerd money" and only meant for super intelligent people.  

I quickly realized I was wrong and that you do not have to be a genius to use the technology.