When would anyone in this day and age would need to know how to bow or curtsey?
I certainly wouldn't see a need to ever curtsey to anyone but I suppose some countries still teach their youth that they are inferior to other people while I was taught, and teach modern Australian youth, that we are all equal and that no one is better or worse than anyone else.
Anyone who bows or curtseys to another person is actually saying to that person 'I am inferior to you' and I don't believe that is the case between people.[/QUOTE
As for who would need to ever curtsey or bow - I'll take the question literally and would say ballet dancers, opera performers, entertainers generally.
It is NOT about being inferior but a mark of respect, either for the audience (as in the examples I have cited) or an individual. you speak in abolute terms and that is limiting. Perhaps you should look at a broader context