Consistent and correct is good, but there are cases where not perfectly correct communicates better than being technically correct. For example, the word "yous". Technically the plural for "you" is "you", but it can be hard to express if someone is talking to a group, if they're talking to an individual in that group, or the entire group itself. "Yous", although not correct and can sound uneducated, often communicates the meaning clearer than just saying "you".