The most irritating and pointless thing just happened to me and some other users. We were helping someone track down his bug. The OP had put the exception message in the question header and some lazy ass had flagged it as a duplicate without bothering to read the question (it wasn't about the exception, that was just the result). We were really active and making progress, with only minutes in between comments. And all of a sudden the entire post was deleted.
Obviously, while people are still resonding there is something worth while going on. So please don't do this, if there has been activity in the last x hours, respect that and let people at least finish their conversation.