1) In the 1970s, wheeled luggage was introduced but clumsy and awkward. In 1989, a pilot developed the roll-aboard suitcase which led passengers to seldom use airport luggage carts, an unintended consequence.
2) The Affordable Care Act was intended to lower insurance premiums but led to the opposite - premiums rose by 9% the first year. Several provisions increased premiums more than anticipated, an unintended consequence.
3) Many state insurance co-ops formed to increase competition under the ACA ceased operations, which will increase the federal deficit more than intended and reduce availability of insurers, demonstrating unintended long term consequences of decisions.