Why do people keep saying I’m 6ft when I’m 5’11” 3/4?

I mean even my own family does this to me. Some of the ladies look me saying how jealous they are of my beautiful height and I am so lucky. They’re like under 5’5”
Even my older sister envies my height and she’s only 5’2 in a half.
My late mother (her step mom) was 6’2”
Anyways even my doctor round my height to 6ft. I told her to put 5’11”3/4 but she said it’s better to round it and there’s no sense of putting that when she can put 6ft.
People don’t listen!!! I AM 5’11” 3/4 NOT 6 FEET!!!! QUIT SAYING 6ft!!!!!!