Following the BBC apology, I have now retitled an earlier posting to "Queen doesn't lose her temper" from the original "Queen loses her temper", and included an explanatory update.
Speaking as a Liberal Democrat Republican (work that one out you Americans), it really is remarkable that, in 51 years the Queen has not been captured on film losing her temper. There has been the odd recorded sharp riposte, but no temper tantrums.
The BBC documentary filmed a photo session where she was wearing heavy robes and a heavy crown on a hot afternoon. The Queen is 81 years old. So the odd sharpish riposte at the suggestion that she remove her crown, and that her formal garter robes were "too dressy", is not unnatural and does not amount to "losing her temper".
The Queen is a remarkable woman. I just wish I could vote for her.