Coffee lovers in the know are probably aware that Starbucks allows customers to enjoy free refills on select beverages, but Blay told Insider that staff members get annoyed when customers don't know the rules.
"Some drinks are eligible for free refills, but a lot of them aren't. If free refills are important to you, ask if you'll be able to get one before you place your order," said Blay.
According to Starbucks, you can get refills of brewed coffee (hot, iced, or cold brew), and tea (hot or iced) during the same store visit. However, the policy only applies if you purchase the original drink with a registered Starbucks card or mobile app.