10 things you should never do in a Trader Joe's, according to employees

Those large bells hanging near each cashier aren't just for decoration. Staff members actually use them to communicate or ask for assistance.

Ringing the bell once instructs staff to open another register, and two rings means that someone at the register has additional questions that need to be answered. Three bells summons a manager.

For this reason, employees don't appreciate when customers or their children ring the bells for fun.

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It's disrespectful to staff members and other shoppers waiting in the checkout line to talk on the phone at the register.

"It really annoys staff when a customer is on the phone in the checkout line and then gets upset when we interrupt them to tell them the total or ask a question," said Morales. "Even worse, some people ask us to wait until they're off the phone."

Morales said that it's frustrating when customers criticize the way an employee bags groceries.

"Staff are actually trained in the best way to bag the store's groceries, so it's annoying when a customer comes in and says that we're doing it wrong or critiques our method," Morales told Insider.

It's perfectly fine to ask an employee to put certain items in the same bag or leave an item out of one. However, customers who are extremely particular about how their groceries are handled should simply bag their items themselves.

Many shoppers may not be aware that Trader Joe's often allows customers to try before they buy.

Customers can have an employee open just about any item for a sample before purchase, but that doesn't mean you're allowed to start opening packages on your own. An employee must be present if a customer is sampling an item from the shelves.

In addition, employees said shoppers aren't able to sample certain items, such as frozen vegetables or baking mixes.

Trader Joe's has a generous return policy — you can bring almost any item back to the store for a full refund, with or without a receipt. This includes food items that you've opened and even eaten, or non-edible products that didn't meet your expectations.

However, the store expects customers to not ask for refunds on products that they have successfully used or enjoyed.

"Trader Joe's is known for its excellent return policy that you can use even without a receipt, so it was always annoying when people abused it," said Wardini. "For example, I had multiple people return plants that they'd obviously killed and then tried to blame the store for it."

Trader Joe's shopping carts aren't as large as those at some other supermarkets, but they can still obstruct the flow of traffic through the store if left unattended.

"Some people just leave their cart at the register and walk away after checking out. The carts are located right outside, so please take it back instead of leaving it in the way of everybody else," said Wardini.

If you don't want to deal with a cart and are only picking up a few items, just grab a shopping basket instead.

Trader Joe's employees are responsible for making sure all items are shelved correctly, so leaving products where they don't belong creates more work for staff.

"It's so much easier for employees if you bring items that you don't want up to the cashiers. If everyone just brought unwanted items to the register, we could avoid hours spent dealing with misplaced items," said Wardini.

This is especially true for frozen items that can be ruined if left out. When in doubt, simply pass the item to a member of staff rather than abandoning it on a random shelf.

The employees at Trader Joe's are known for their friendliness, and being polite in return is always the best option.

Current Trader Joe's employee Valentina Morales told Insider that ignoring staff or cutting them off during conversation is considered rude.

"When I greet a customer and ask how they are, it's frustrating when they either don't acknowledge I said anything or they cut me off and just ask a question about where to find an item in the store. This happens almost daily," said Morales.

Former Trader Joe's employee Lauren Wardini told Insider that staff hate when customers leave food wrappers and sample cups around the store.

"There are plenty of garbage cans around the store, so it's annoying to find trash left on shelves or in carts. This is especially true if the trash was sample cups," said Wardini.

Show your appreciation for the free coffee and food samples that are often offered at Trader Joe's stores by depositing your used cups, utensils, and napkins in the provided trash cans.

Former Trader Joe's employee Joseph Sleek told Insider that employees hate when customers ask two staff members to search for the same food item.

"Customers often asked me to look in the back of the store for something, and it really bothered me when I'd come back out to find that they had asked a different employee to check in the back as well," said Sleek.

Rather than sending multiple members of staff on a hunt for the same out-of-stock item, it's oftentimes more useful to ask an employee when they expect that item to be restocked.