You think you are, but you're not

Some people think it's cute to correct other people's grammar and writing. Don't. (A few people in certain occupations are exempt from this directive. It's most likely not you.) Your desired outcome of sounding smart will backfire when you in fact make yourself look not smart by being wrong. If you can't help yourself, check the Chicago Manual of Style first. And I can't promise that even doing this will make you as cute as you think you are.