My Dad used to tell me that I was tall. He probably hoped I'd take after him, 5' 11" and slim till he died at 89. However, this had the effect that I walked with a stoop as I didn't want to stand out. I have never really got rid of it, but I didn't grow o be tall. I am 5' 5". Thanks, Dad.
If I concentrate, I can walk straight, and it does make a difference to your confidence and attitude. It also helps to wear nice clothes and take a general pride in your appearance. Hard to do when you're wrinkly and flabby and loaded down with shopping bags, though.