Nobody's perfect, we all have some bad habits. But it requires a high degree of self-awareness to keep in check the bad habits and taking corrective actions towards them. The thing about habits is, it's not easy to put a tag on them. Often the way someone perceives a habit to be bad depends on one's values, attitudes, and personality. As a result, a person's behavior may be perceived as cute or obnoxious. Although there is a fine line between them.
Let us see the difference through illustrations.