You get hurt and need a "bus" to the ER. EMT is a hobbyist. Or the ER doc. Or the x-ray guy. Or someone.
You walk into Best Buy and voice from behind says "can I help you?" and it's the guy you saw yesterday.
In my profession (medical) there is a serious and distinct cut-off. If I see you, I don't say a thing unless you say hi first.

