What is the worst or the most disrespectful chess opening ever existed?

I think what you're looking for is the Bongcloud, named after the great chess theoretician Lenny Bongcloud: https://www.chess.com/member/lenny_bongcloud

Even Garry Kasparov has never beaten the Bongcloud in a rated game, though he did scrape a win in a casual online game:

Note that Kasparov is playing against the Sicilian Bongcloud here as opposed to the pure Bongcloud which would go 1. e4 e5 2. Ke2 , but similar ideas are common to both.

There is no such opening.

What does exist is people who get offended by anything.

The thing that annoys me the most is when someone plays the London System

one of the most boring and tedious systems out there.

But if they play 1. f3, 1. a4, or the Bongcloud, then wonderful

thanks for the advantage on move 1.

Maybe their idea is to beat me psychologically, but I’m not going to take it badly or feel intimidated.