"Son, don't let nobody take your watermelon", was a phrase my grandfather used often when I was a kid, referring to something you had of value that others wanted. Sometimes others will try to devalue what you have in an effort to make what they have seem better. Their efforts to make what you have meaningless could be a by-product of envy, greed, jealously or spite.
Industry along Mobile's riverfront. Photo by Karen Savage, flight by Tom Hutchings