I can only think of three brands that I would absolutely never buy again: Wen, Tweak'd, and Perfect Gourmet Potstickers.
* Wen made my hair fall out terribly.
* Tweak'd volumizing formulas make my hair very dry, and straw-like brittle.
* Perfect Gourmet Potstickers are delicious. But they taste like the exact same potstickers I get from Trader Joe's (Gyoza), at a fraction of the price.
Other than those three, I don't eliminate any brands as a whole. But I buy less & less because of the narrow, boring offerings, and high prices for what you get.