Pisses me off whenever I put in a sentence or word to translate and decides that my word is incorrect and changes it to what the add-on believes it should be. It's like Google's 'Did you mean...?' except this addon says 'No, you are wrong. What you really meant to say is what I say you mean'. Infuriating. Good apart from this, but since it keeps translating the wrong words, it's pretty useless.