Well, I have to address the phenomenon, aka the elephant-in-the-answer box.
But first things, first. Voting on the worthiness of a question is not the same as voting on whether an answer to a question is good.
For answers, I upvote an answer based solely on my understanding of the question and deciding on which answer best fits the bill. Sometimes, two answers may be good or cover more ground together than separately. So I upvote two different answers.
The phenomenon that drives me round the e-bend is: upvotes on answers that are completely off track when a good answer is present but has gone unrecognized by all the upvoters.
I call this: the null-set or shiny-pretty-thing bias. That is a polite way of saying the upvoters simply don't have the knowledge to know either way whether an answer is actually really good. They read an answer, don't know the subject matter, and upvote because everything "sounds good". They vote for the shiny, pretty thing. The incredible part of this is that often this occurs in a context where a really good answer is present and overlooked. When I really do not know the subject matter, I do not vote. Period.
The other phenomenon is that the right answer is completely different from what most readers (voters) are able to recognize, and, not only do they upvote what everyone else has upvoted, they downvote what is actually a good answer but one they simply do not understand.
Unfortunately, there is a lemming effect, and people do seem to sometimes just follow the crowd. What other explanation can there be to explain a huge number of unmerited upvotes for certain answers? And also, the converse: a large number of unmerited downvotes on certain answers?
Please note: I only am commenting here on answers, and not on questions.
Re this question: I think it is useful, so I am upvoting it.
Re the answers: I think they all say something useful, so I am upvoting all of them; they each add some interesting insight on how people vote.