The act of mob-mentality buying means the investment is overvalued. Whether pot penny stocks, Bitcoin-related businesses, companies from the dotcom mania, or Dutch tulip bulbs, you will never get a fair price.
Another unfortunate side of this equation is that when the majority are hearing about the latest craze and jumping on board, the stampede is just about to come to an end. Fortunes will be invested and lost within weeks, if not days.