Hateful action is the only physical evidence of envy, which cannot otherwise be proven. All people publicly accused of the shameful emotion of envy will deny it because they can.
The goal of advertising is to make us unhappy with what we have. Advertisers have to walk a fine line though, because envy seeks to destroy, not compete. Advertisers need us to go out and buy a new car, not torch the neighbor's Hummer. I wonder if the eternal popularity of socialism/communism in a capitalist economy is driven in part from poor advertising.
When accused of envy it is best to make a joke of admitting to it whether the charge is justified or not. To deny envy only makes the charge stick. I don’t mean to make a sarcastic admission but a good humored joking admission.