Compromised Customer Service due to pressure.

Was at McDonalds Highveld Mall in Emalahleni, seems like the cashiers at this place loose their temper when it is a busy day for them cause this is not the first time I experience such at this place. Today's experience was the cashier at the drive through named GIVEN( if he gave me he's real name cause he wasn't wearing a name tag) was very rude which is totally unacceptable because no matter how tired they get, patience and a smile is key to good customer service. I understand that they need to be fast to push the queue, but if that's going to be at the expense of their customer service then, they rather be slow.