Smart people often think social institutions are basically arbitrary and that they can engineer better ways using their mighty brains. Because these institutions aren’t actually arbitrary, their tinkering is generally harmful and sometimes causes social dysfunction, suffering, and death on a massive scale. Less Wrong is unusually bad in this regard, and that is a serious indictment of “rationality” as practiced by LessWrongers.
Pff, this one is so normal it has an obligatory link :D
Another relevant link.