Recently, Ms. Schneider and her college-age daughter were excited to find Ugg boots, Smashbox makeup in leather cases and Seven jeans at their Costco in Nashville. “Costco seems to go for the upper crust in taste,” she said.

Some offerings rotate in and out of the warehouse based on the season, sales volume and other factors. As a result, people may go to Costco more often than necessary to see what is new, said Steve Hoch, a retail professor at the Wharton School of the University of Pennsylvania. “When they see something they want,” he added, “they’ll be likely to go ahead and buy it, because next time they return, the item may be gone.”

While most consumers become annoyed when something they expect to find at a store is out of stock, a Costco shopper is likely to think, “I should have gotten it last time,” Professor Hoch said.

Other retailers may also seek to entice shoppers by setting limits and creating scarcity. For example, Target offers limited-edition designer clothing and home furnishings that are unique to its stores, and that are often stocked for a period of only 60 to 90 days.

And at BJ’s Wholesale Club, customers may come for their everyday grocery items, “but if they spot some jewelry or the new capri pants at a great price they will be happier,” said Teleia Farrell, a company spokeswoman. BJ’s uses items like 42-inch televisions and topaz rings to turn “ho-hum shopping into an exciting environment,” she said.

It is the same at Sam’s Club, where “members enjoy looking throughout the club for unexpected deals,” said Susan Koehler, a spokeswoman for the company.

Temporarily stocked surprises are also a calculated part of the Costco shopping experience. “We try to have hundreds of items that are different each time a customer comes to the warehouse, to create a treasure-hunt atmosphere,” said Joel Benoliel, a senior vice president. “We’ll always have the same staples — the cereal, the detergent — and then we add in the ‘wow’ items.” But at the same time, there can be a comforting sameness to each cavernous location.