The bakery is switching to smaller muffins and will no longer offer mix-and-match muffins. Instead of mixing and matching two 35-ounce six-packs of the larger muffins for $9.99, warehouses are selling one 31-ounce eight-pack of an individual flavor for $6.99.

Costco loyalists are known to rave about everything from the food court (with its decades-enduring $1.50 hot dog deal) to the chain's line of exclusive, high-quality Kirkland Signature brand grocery products and even cheap booze.

Costco customers have been left fuming after the store made a change to its much-loved muffins range - and they're not happy about the new deal