[dvtrn]

and if you entered it means you already decided to purchase something there unlike e.g. being approached by a sales person on a sidewalk or getting a sales email.

Until you start getting incessantly upsold to a 'vente' or upsold to add a bagel.

I thought a friendly "no, that's okay, thank you" and a smile was enough but there was once a national brand franchise coffee shop that badgered me enough during the checkout experience, and on frequent enough visits when I'd get off the train and walk in for a cup of joe along the way to the office that I stopped going.

"I'm just trying to help you get a deal on your coffee".

Friendly, polite, chipper...probably pressured by a GM to upsell but I feel once a customer has politely turned down an upsell, maybe one more "are you sure?" and then after that just give a person some grace and let them buy what they've asked for.