This question already has an answer here:
The answer that sparked the question is this one where the answerer provided a completely wrong answer to the question and was consequently heavily downvoted. However, the answer seems to have appealed to the OP's preconceived notions so it was accepted. Of course, the system is designed to allow the asker to choose an answer that was helpful to them; however, it's well accepted that the most important posts are those that are helpful to the far more numerous readers who come across the question from Google or somewhere else rather than the original asker. They should be shown the answer that the community deems best. In this case there's a perfectly good answer with a score of +5. That's what readers should see first. Not the post that the OP decided (against the judgement of everybody else) was best.