Is there any nuance difference between saying "I'm so late" and "I'm too late"?
Native speaker’s answer
Rebecca
"I'm so late" implies that one is very tardy for something, like to a party. "I'm too late" is much stronger and implies that one is so late that there is no hope, like being too late to board a flight. Ex: I'm so late for Sarah's birthday party. I hope she won't be angry. Ex: I'm sorry Sir, we cannot let you board this flight. You are too late and the plane has already began takeoff procedures.