Brand Vendetta, the slight opposite of “Brand Loyalty” is when a person dedicates a chunk of their energy solely to hating a singular or a group of brands. Maybe from past wrongdoing by the brand or their air of superiority and the need to be above other people. For example in the recent time of 2020 or the past year when Apple released a new product, just like their die-hard fans who will line up to buy it, the haters will be ready to berate the brand and their customers. The other notable event is Intel CPU vs AMD CPU. Usually "Brand Loyalty" and "Brand Vendetta" come hand in hand like Samsung fans to Apple fans or PlayStation fans to Xbox fans.
To simplify: An act of hate that is solely based on a brand.
Mike: " Hey Y'all see the new iPhone? It's so stupid, right? I can't believe they take the charger out of the package. What are they going to do next? Take the phone out? That's why I'll always stick with myInsert non-descript brand of smartphones here.
His Friends: " GOD! Again with mike, Every year he goes on and on about apple this intel that. Can't he just shut up and let go of his Brand Vendetta?"