Why are restaurants rude to us?

Are ppl rude to you or is it just my area?

Today I picked up a mcdonalds order. The employees kept walking oast me so finally I asked one if my order was ready she would NOT let me talk, just kept snapping her fingers at me to give her the order number NOT the name...got through all that and door dash prompted me to ask if the drinks were in the order. She got really mad and yelled and said if I made it then it's in there. I tried saying sorry and she PUT HER HAND IN MY FACE and told me "BYE" And she was the MANAGER!

I get ppl like thus everytime, but I'm not sure why they're so rude???