But why is Costco pizza so addicting? Consistency is key to keeping Costco food fans happy and there's a science behind their pizza, making sure every slice delivers the same familiar taste each time.

Costco cheese pizza in a Costco food court box - grandbrothers/Shutterstock ...

Half of a Costco pepperoni pizza in the box - grandbrothers/Shutterstock ...

After years of anticipation, the bulk-buy retailer has finally opened a gigantic new warehouse in Ardeer, in Melbourne's west ...