Large Starbucks cup of water
Don't Do This When Ordering Free Water At Starbucks
When asking a Starbucks barista for water, don't try to cut the line. Stay in the line patiently and wait your turn to order, even for this free amenity.
Interrupting the barista's flow leads to longer wait times for everyone in the store, which jams up service. What seems like a simple ask is really just an interruption.
Adding on a cup of water when you pick up your drink is essentially the same thing. Instead, ask for water with the rest of your order so the staff can be organized and efficient.
Remember that hospitality goes both ways. Being a considerate customer helps keep free services available and makes life better, both for the staff and those in line with you.