Let's see...

Cereal! Much as it galls me how much cereal costs, the generic just doesn't taste the same.

It has to be Hellmann's mayonnaise. No other will do. I'm irked that you cannot get it in glass containers anymore; don't they realize how much can leach from plastic into an oil based product?

Glad or Hefty garbage bags; they have a higher thickness (mils) than the generic stuff, so the failure rate is less. (Kitty litter, anyone?)

I prefer brand name ice cream; life's too short to eat cheap ice cream!

For a lot of products, private label (store) brands are very good. BJ's
scoopable kitty litter is first rate.