Regarding bubbles, the Great Depression 2 was caused by inflated home prices, the result of false demand from unqualified buyers. Now we have inflated home prices caused by very low interest rates. Rates are going up, making the mortgage payment go up. Demand will drop, and prices, too. Recall from the Great Depression 2, that even folk who could pay their mortgages walked away when home prices dropped, and their "investment" became underwater. Stay tuned.
https://www.usnews.com/opinion/economic-intelligence/articles/2018-01-30/janet-yellen-didnt-set-up-jerome-powell-for-success-at-federal-reserve