kdramas that are not a waste of time

kdramas that are not a waste of time. criteria: "would i be able to or want to watch this again sometime in the future?" has a focus on: crime, murder, mystery, detective, military because the way they are set up throughout the entire series keeps me engaged and makes watching not a chore. min/max your time and stop watching: - athena, after 16 - gapdong, after 16-18