I think most of us have seen it. You post something innocuous, it receives an upvote, then another, then another, and before you know it you've got another handful of badges pinned onto your chest.
Now I know that rep shouldn't matter and all that, but I also know that I'm only human. I do have a certain feeling about the quality of a question or answer that I post, and certain (subconscious) expectations about the number of votes it will receive. And sometimes it just happens that the actual number is very different.
What question or answer have you posted, that unexpectedly received way more upvotes (or downvotes) than you had expected?