Jim Chanos talked about this almost 10 years ago, on Chinese plan to build 5 billion square feet of commercial real estate, the residential bubble aside. Most of the coastal cities in U.S have exceeded the 2007 bubble levels now. There's an unburst real estate bubble in Asia, which pretty much escaped the 2007 crises in the U.S. Then there's the bubble in Bitcoin, ICOs, Collectibles. Stocks will soon enter the bubble territory if we rally another 200-300 SPX points. Then we have the Student loan bubble and Car loan bubble. Debt being the mother of all bubbles - private and public. Never seen so many bubbles going on at the same time.
China RE? That's where they stash their money, empty or not. They don't care if there's no tenant.
Bitcoin? A tulip-time joke. There's a sucker born every minute.
ICOs? Further tulip-time.
Collectibles? An even more minor, tiny joke. They collapsed a long time ago.
Stocks? Bubble level may be at about DJIA 100K. US companies actually earn real money and pay real dividends.
Student loans? Who cares? Idiots are soon parted from their money, and so they have been, they're waking up to the scam.
Car loans? What bubble? Auto balances aren't even keeping up with inflation. Not to mention that auto loan balances are fairly well-secured. Repo guys get paid well for a reason.
Your "bubbles" other than imaginary and goofy, minor stuff like bitcoin don't exist.
Not a single good reason to sell a single share of any stock.