Dear Miss Manners: As an American, if I meet the Queen of England, am I required to bow to her?
Gentle Reader: Where were you during history class?
Never mind. Here is what you missed:
We Americans fought a revolution against the British crown. As Miss Manners trusts that you will be relieved to hear, we won. Therefore, we do not prostrate ourselves before someone who is not our sovereign — just as the British bow to no sovereign but their own.
But we do not even bow to our own leaders. Although we believe that all human beings are worthy of respect, we do not believe that any one of them is born at a higher level than the rest of us.
Therefore, we perform the symbolic gesture of bending our knees in subservience only to the Almighty. That, Miss Manners supposes, is why debutantes curtsy to Society.

Dear Miss Manners: Is it particularly improper if someone verbally disrespects the president of the United States? In particular, a citizen of the United States would be the person expressing disrespect.
Gentle Reader: Where were you during civics class?
Never mind. Here is what you missed:
We Americans have freedom of speech and do not consider disagreement with — or criticism of — our leaders to be disrespectful. Their words and actions are understood to be open to general opinion. Even satire is understood to go with the job, and we expect it to be accepted with good nature.
If, however, you mean outright vulgarity and viciousness, that would be improper toward anyone. In regard to the president in particular, it also violates the unwritten rule (although Miss Manners is now engaged in the act of writing it) that we show respect for the office, in the person of the officeholder, even if respect for the individual is lacking.
That is in contrast to countries where the forms of respect are mandated by strictly enforced law. Our pride in our form of government, where the leaders have been chosen by the citizens, should be enough to prompt a voluntary show of respect.

Dear Miss Manners: Is there a ladylike way to get in and out of a convertible sports car in a dress and high heels??!!
Gentle Reader: Where were you during posture class?
Wait — you mean there is no longer any such thing as posture class in college? When Miss Manners was an undergraduate in a female institution of higher learning, posture was a compulsory course in the physical education department (and, as you can imagine, she excelled at it). It included mastering exactly such situations as yours.
So here is what you missed:
As soon as the door is open, swerve toward the curb, so far as is possible in a bucket seat. Keeping the legs together, plant both feet on the street, which is probably not far down. It will then be slightly easier to complete the swerve until you are sitting sideways and can crouch enough to clear the doorway and stand on those feet.
Now — were you also absent the day we learned how to lift a suitcase into an overhead rack?