I TOTALLY agree with your Grandmother. I would say that it does also extend to manners and such.
I agree with this, too, and have to extend it to other people. When dd1 was little, it took her a little while to warm up to new people, and so many people would say "oh, is she shy?"My late Grandmother gave me the best advice regarding raising children and it is so true!
"Your child will act the way you expect him to act."
She did not mean this in regards to manners, she meant it more in regards to - "Oh, he won't eat that!" or "He is afraid of dogs" and the like.
My Dad's best advice? "Keep your head out of your a$$" .He passed in October 2008.
Go with your gut feeling.
from everything from clothes to jobs. your conscience is almost always right.