6. If you have ruined your past relationship with some other girl, don’t tell that to your girlfriend. Even if she asks a decent reply would be that you don’t want to talk about that. She will understand if she loves you and even if she doesn’t, she should understand.
7. If there’s another girl who is jealous f your girlfriend and she considers her worst enemy, don’t let her know that that enemy should be the one you already like so much. She might get offended and this may turn into a very bad fight.
8. If you have had a bonus on your work, or a salary increase, don’t tell your girlfriend. Then, you won’t be able to save and she will spend everything you have quiet generously. That’s how women are, no offense.
9. You might think that she is on her period, but there is no need to initiate such a discussion. Your girl might feel insecure if you try to tell her that you know. Even if she has visible signs on her face, don’t tell her that you think she is on her period.
10. If you don’t like her friends, ignore them. That’s all. You don’t need to tell her that because then she will tell you about your friends and things will turn out really bad, which you do not want at all.