Ancient Greek style is fine. If you use enough olive oil, the fungus just slides right off.

Why do you think the reason needs to be explained at all? Every site that uses an up/down vote system has pretty clear guidelines on how they are meant to be used, so either the user is voting according to those rules, or is using it as a like/dislike button. Commenting is typically reserved for contributing to a conversation, and in most instances, justifying a vote ends up being either noise, or comes off as complaining about Internet points.