Advise: Something that most people ignore. To each their own. As you get older, life experiences teaches you many lessons. Years of knowledge and experience not only of what to do, but what not to do. It's probably been this way for generations. Younger generations that have the world in their pocket and know everything, therefore are not receptive to anyone's advise, let alone someone older, like a grandfather. Then as a grandfather you watch them make mistakes over and over again as they ignored your advise, disgarding your years of experience and knowledge.
And while you find a Subtle diplomatic way to convey to them... "I told you so"... It's all for not. For nothing changes and they are destined to learn the hard way all on their own. But that's American society.