OP, you are too hard on yourself! the car story is AWESOME!!! hilarious! I have 9 yo and YES!!!!!! it's like that!!!! I think more mama humor will help me!
no actual suggestions, just stop blaming yourself. we love them but they are annoying. on the other hand, i do think their lives are hard, and for the first time it's more hard than fun and i suspect they don't know what to do with this, and are thinking life is just going to get worse, and never better.
I find it disturbing that the car incident is considered inappropriate/non-GD. you were sitting right there. you juxtaposed the situation to shake up her perspective. you did not humiliate her. you did not terrify her. you did not endanger or abandon her.