In a relationship, if the other is not doing something immoral, illegal, destructive or disrespectful, we have absolutely no right to try to force him or her (by coercion, manipulation, or whatever) to change to fit our idealized vision of what he or she should be. In fact such action is disrespectful. If we find that the other is doing something that simply bothers us deeply, yet which is moral, respectful, legal), that person is simply not the right fit for us.
This is why it's best to have all cards on the table from the very beginning, so that both partners have the opportunity to make a determination about what they can or can't tolerate. Sometimes, though, after years of living together one partner throws the other one hell of a curve. That can be a real nightmare.