Bubbles are inherent to Human Behavior.  People see other people doing something they want/like/need and start jumping up and down on the band wagon to get it.  More people see people doing this and start doing the same thing.

Eventually the wagon breaks.

Reference: Extraordinary Popular Delusions & the Madness of Crowds, a book that everyone needs to read.

She believed in nothing; only her skepticism kept her from being an atheist. -- Jean-Paul Sartre