The next president will appoint two Supreme Court nominees. Both houses of Congress are controlled by the Republican party. Gay marriage and abortion very well could be reversed, quite easily actually if conservatives control Congress and have a majority on the Supreme Court. That fact, combined with conservative views on climate change, are why I think it would be extremely extremely harmful not to have someone in office to veto.

"I’m not so sure the economy has turned around other than for the few and that the ACA is going to work."  By every measure, I practice economics. GDP growth, job growth, unemployment rate, budget deficit, market capitalization.

I hope you don't have to see the effects of votes for Gary Johnson resulting in a Trump presidency.