Grammar tells us how we should apply the rules for our exact communication. To study grammar is like an exercise for the mind, a form of analysis, a mental exercise similar to chess, crossword puzzles, or Sudoku. Grammar is a means to help us communicate our thoughts clearly, precisely, and with a purpose. Grammar courses and exercises will teach you why certain constructions are incorrect and how to fix them. Whatever the reason you have to learn grammar, you will never regret to have done it.