no-use

I remembered what Dad said once, that some people have all of life's answers worked out the day they're born and there's no use trying to teach them anything new. 'They're closed for business even though, somewhat confusingly, their doors open at eleven, Monday through Friday,' Dad said. And the trying to change what they think, the attempt to explain, the hope they'll come to see your side of things, it was exhausting, because it never made a dent and afterward you only ached unbearably.

You have the beach but not the sea? No use! You have the sea but not the beach? No use!