I think Queen Elizabeth II was extraordinarily lucky to be born with the sort of personality she has, as this has been a major factor in allowing her to carry out her duties so admirably. If she had been more like her Uncle David, or even her sister Margaret, for instance, the British Royal Family might not have survived into the 21st century.
I realise that a lot of it is due to her own efforts and a huge amount of hard work, but if she had not been born the sort of person she is she could not have done it.
Just imagine some of her relatives in the position, like Tsar Nicholas II of Russia, who broke down in tears when his father died as he didn't want to be Tsar, and had no idea how to do it. Or QEII's ggg Aunt, Victoria, Empress of Germany, who was extremely clever, very politically minded, and was so disastrously unaware of other people's feelings that even her friends said that she was her own worst enemy. Or Victoria's son, Kaiser Wilhelm II, who brought Germany to its utter ruin, and helped cause the First World War.
Her father George VI didn't want the position either, and he is said to have sobbed on his mother's shoulder when his elder brother abdicated, but he did the best he could, despite having the wrong sort of temperament to do it at all easily, and it brought him to an early death.
Instead, Elizabeth II has remained as Queen of various realms (presently 16 in number, with a different title in each one) for nearly 60 years now, and she is widely respected and admired. I don't expect that she enjoys all aspects of her job (very few people do, after all) but she has had the ability to cope with the things she doesn't like, without any apparent strain. That might take a lot of effort on her part, of course, but if so she doesn't let it show.
I find some of the fawning on this thread a little nauseating, but that's purely my own personal reaction. I admire Queen Elizabeth a great deal, not so much for her 60 years of Service, as for her 60 years of EFFECTIVE Service to her country. I don't think the British Royal Family would have survived this long without her contribution, though of course that might or might not be a good thing.