We all have...thus being overgross is not the mortal sin it is made out to be
not often I disagree with you (except of course your during strong lobbying for a tea total world!), but I want to call you on this one. I agree the machine will not catastrophically fail, etc etc, but it is akin to the jelly bean jar of Nick Lappos.
When you fly over gross, you are using more jelly beans faster than the designers intended. If you fly well over, then you are also likely to be exceeding design strain limitations of both dynamic components AND the static airframe ones. By going over gross you are hoping that you have not caused undue fatigue, or even caused the accelerated propagation of a fatigue crack. You hope, but you dont really know.
Either way, it is unlikely that you will suffer the consequences of your excessive jelly bean use - it is more likely to be the subsequent pilots, ignorant of your jelly bean consumption rates, that find the jar unexpectedly empty.