I want minus button in forum messages, thet decrease rating of message, becouse i really don't like some stupid suggestions, mods and other dull messages. Please add this, so people will know, is mod or suggestion interesting, or not.
It was here. There even was a downvote army for which it was turned off globally. It's really easy to down-rep someone when you have a minus button, just going around and downvoting everything. But, as any self-respecting forum knows, that never leads to good. It provides a faulty reputation value easily diminished by downvote armies and the minuses just look ugly.
The idea would endorse the use of the button to the point at which no constructive criticism would be made, and therefore the OP would never understand why their idea was bad/why they should change it.