Stress may lead people to harshly critique and correct others that violate rules of grammar or make spelling mistakes. A side-effect of the recent economic crisis, psychologists claim, is a wide-scale increase in grammar retaliation.
An obsession with fixing punctuation may reveal a psychological need in individuals that craved to please adults during childhood, or they are an obsessive perfectionist. No doubt, the rise of 'teh internetz' has contributed to their distress.
Recent signs of this include the 350,000 strong Facebook group 'I Judge You When You Use Poor Grammar", people correct billboards on the streets, and in 2008 two 'grammar vigilantes' were charged and fined for correcting signs on Federal land.