People toss around that type of sentence like a jest until things abruptly become true. One moment it's casual, practically comedic; the next it is heavy. Once those words are in the room, it means something has changed. It is now beyond chat. It's getting really serious currently.
Sometimes it derives from pals, spoken with a smirk following a tiny error. Other occasions it arises in strained times when no one is laughing. That's when it strikes you. The strain. The understanding that things might not be as simple as you believed.
Beyond the legal definitions, though, it also speaks more personally. It is about defending oneself. Knowing when a circumstance has become too much for you alone.
Not every issue calls for that kind of defense. Most circumstances, actually, may be fixed with honesty, patient dialogues, and a little empathy. But there are times when you have to be cautious, when words matter, and actions have effects.
That is where the mood of the phrase shifts.
It stops being spectacular and turns pragmatic. Not everything is informal, therefore not every event may be dealt gently.
Superior legal approach.
Not always because you are guilty, but rather because sometimes only wise choice is readiness.