久惯成病

'jiuguanchengbing' means 'a longtime habit will become a disease.' This could refer to how habits can turn from harmless to damaging over time if they remain unaltered and also reflects the user's view or feeling that a certain long-held trait or habit is a negative aspect they possess. In another perspective, it represents an ironic tone that bad things happening continuously can turn out normal and thus 'become a disease'