Have you ever had somebody say something so stupid that it sucks the intelligence out of everything else they say? As if you are averaging their intelligence across their comments. Or are you averaging their stupidity?
Tech support from our printer supplier emailed me to say the user complaining about a smell and noise when they print may "have no toner cartridge installed." I don't know about you, but my printer doesn't print at when the toner or ink cartridge is removed. The printers are intelligent enough to know this, apparently some printer techs are not.
Their next suggestion was actually very insightful and under normal circumstances could have been considered brilliant. Since the printer was reporting toner level at 0% they suggested that installing a fresh toner may resolve the "burning smell" issue. Of course! Why didn't we think of that before?
Unfortunately the ballast of the first comment is dragging the second one down so it is no longer 'brilliant' or 'insightful'. Instead we just have a 'good idea'.
A similar effect can be achieved by stating something intelligent followed by something stupid. In IT support we often see this from Cliff Clavin-type users who say things like "I ran out of hard drive space. I need more RAM" In this case the stupidity is retroactive.