i've never really had an issue with just saying "would u like to speak to a supervisor?" usually they say yes and i go grab them and explain what's happening. i'm a 3 month partner at a very busy location with frequent shortages so normally people are nice about ordering something else. i feel like at this point some customers really want to take their misery out on us because we just have to grin and bear it. my supervisors and SM are really nice and support all the baristas at my store so i know that they'll have my back if a customer is being absolutely horrible to me in drive. it's just ridiculous that we have to deescalate these situations when we have no control over it.