Why do registered voters end up not voting?

[MarkD]

There can be many other reasons. In my case when I decided,  in Dec. 2002, that I never wanted to vote again for the rest of my life,  and I didn't vote at all until March 2016, it was because I was disgusted with the Supreme Court's decision in Bush v. Gore, and more generally,  disgusted with all judicial activism, all the occasions in which the Supreme Court legislated from the bench. The Court could, some day,  prevent my vote from being counted, or strike down a law I voted for, and which I was sure was not truly unconstitutional. One of my Republican friends asked me, "What if they raise your taxes?" I replied, with much agitation in my demeanor,  "Why should I bother if the Supreme Court can hand down a ruling that prevents my vote from being counted?"