NORTH CANTON, Ohio  A simple change to the design of the gallon milk jug, adopted by Wal-Mart and Costco, seems made for the times. The jugs are cheaper to ship and better for the environment, the milk is fresher when it arrives in stores, and it costs less.

What’s not to like? Plenty, as it turns out.

The jugs have no real spout, and their unorthodox shape makes consumers feel like novices at the simple task of pouring a glass of milk.

“I hate it,” said Lisa DeHoff, a cafe owner shopping in a Sam’s Club here.

“It spills everywhere,” said Amy Wise, a homemaker.

“It’s very hard for kids to pour,” said Lee Morris, who was shopping for her grandchildren.

But retailers are undeterred by the prospect of upended bowls of Cheerios. The new jugs have many advantages from their point of view, and Sam’s Club intends to roll them out broadly, making them more prevalent.