"Bad habits" is a subjective term. There's a lot of people that consider smoking a bad habit yet billions of people do it and enjoy it. I think biting your fingernails is a bad habit. Hell, my preference of one particular body wash could be thought of as a bad habit. Some things are dealbreakers, others are not. People in a good relationship can identify which habits fall in to each category and move in the appropriate direction from there. They just need to be honest with themselves, and each other.

That seems to be a reasonable approach to most of life’s challenges.