Costco is great for purchasing in bulk, but it isn’t always the best option for everything.

The company’s offer to consumers and the way they operate is quite unique, and according to some Costco workers, the membership gets into people’s heads and causes them to forgo on manners or second-guessing the deal they’re getting sometimes.

Costco’s products and food courts have launched the wholesaler into worldwide popularity. On top of this, Glassdoor’s list of best places to work ranks Costco highly. However, according to dozens of Costco workers who spoke with Business Insider, being a Costco member doesn’t entitle you to whatever you want. Some of the things that they want to let you know would save you some money on your next trip to Costco, but they also had plenty to say about the inconsiderate behavior they’ve experienced.

First of all, even though the membership card isn’t commonly used outside of Costco, employees want you to remember to have it ready at the exit. Beyond this, there are obvious things which some members do which are simply wrong, such as littering the aisles with sample cups and other trash. They’d also appreciate it if customers would return items back to where they got them and not leave a chicken thigh in the produce section. Of course Costco employees won’t tell you to do any of these things, as they aren’t allowed to.

Among the things that Costco employees would like to tell you that would lose them their job, there is the fact that the sale price isn’t always the best price. Furthermore, Costco’s produce deals are not always the best deals you’ll find. The company’s wholesale business model makes it so that buying fruits and vegetables is quite often better elsewhere.

For the most part, common courtesy will calm most Costco employees’ internal agitation, but don’t expect a Costco worker to tell you about a bad deal while on the job.