Th decision not to vote was difficult, but I think the truth is that real power no longer resides with the POTUS, but with the abstract and inhuman demands of what we still laughingly call "the economy."
So it seems misleading to pretend that the identity of the POTUS is a significant matter, and participating in the election would give that impression.
In addition, a vote implies an endorsement, and I can't endorse any of the candidates.
Finally it seems to me that the difference between Hillary and Trump is a matter of style, not substance. I'm convinced that they would do exactly the same as each other if elected. Only Hillary could get away with it more easily, because of the residual perception that she is somehow a "liberal." In my opinion that makes Hillary worse than DT.