You and I both know that there is a long history of bubbles. Most recently the real estate bubble and the dotcom bubble.
I think the biggest problem is that we (the govt) didn't let the last bubble pop. As soon as it started to rapidly deflate in September of '08 Bush and Obama did everything they could to keep it inflated. Stimulus, bailouts, virtual zero interest rates for years-on-end, the printing press churning out $80B/month in the endless QE3. In my opinion the economy now is an illusion, a dangerous illusion.