Serious as a heart attack. Everything from non branded low quality gas to cheap Chinese crap on the shelves, to rotten meat and spoiled produce. There is nothing good about Costco unless emergency shopping as last resort. It's a bulk product provider that encourages hoarding.
I just use my Amazon Prime membership for same or next day delivery when I'm hard up for Warrens cheap Lubrigard/ITASCA oil that Walmart and Costco sell. When I need gas I go to Chevron or Shell and pay a few cents more a gallon in and out in less than 5 minutes. And I can wash my windows and check my oil. Try that at Costco and there will be a riot and assault for holding up the line.