To start off, GO IN AND ORDER.
I have went through the drive through multiple times and have gotten my ordered screwed up-and it isn't only this mcdonalds.
But here's a story about this drive thru that made me laugh more than upset ( this happened to me): I ordered a premium grilled chicken sandwich, without cheese of course. We pulled up, paid then awaited at the next window for our food. We got it and everything was there. I opened my box to eat my food because I was so hungry. I checked for cheese and you won't believe it....they forgot the chicken on my chicken sandwich! I laughed for awhile and couldn't believe it- I went back and they were shocked as well- but I got a new sandwich-chicken INCLUDED this time.
Just don't go through the drive thru, it's best to go in.