1. Making a phone call
Doing this while in the drive-through is just terrible! You leave the attendant confused as he/she can't determine which part of the conversation is even directed at her.
Ultimately, you annoy other customers as you slow down the line. Stop!
2. Being indecisive about what to order
This is rather common and even more so when you are new to that particular drive-through. One way to avoid this is by making your decision before you reach there.
Is it coffee and jammy doughnuts to help you kickstart your day? Whatever it is, always decide before reaching the drive-through.
3. Speaking inaudibly when making your order
This can be quite nerve-wracking for the attendant as he/she hurries to get you everything to make the line go on faster.
Many drive-throughs provide a microphone for customers, but not all have it. When they don't, try to make yourself more audible by leaning forward and speaking louder.
4. Ordering for a crowd
Drive-throughs are meant to provide quick attention to customers. If you and your pals drop by and start to make a large order, it can be deemed inappropriate as you delay many other people on the line.
It would be more courteous to go to the main restaurant and order takeout!
5. Changing your order at the window
Once you've pulled up to the window and made your choice of food, the workers immediately start preparing it. Changing your order will slow things down, so it is just better to go inside since you have enough time to change the order.
6. Causing a lag in the line by not pulling ahead promptly
Again, the most crucial thing about drive-throughs is that they provide orders at a quick rate. You should never do anything to impede the flow of cars; move ahead when you should!
7. Interrupting the attendant
Whether you're in a hurry or not, it is bad manners to interrupt ANYONE while they are talking. It is usually a part of the attendant's job to offer greetings and little information about what they offer, etc.
So, calm down and let him/her do so before placing your order.
8. Passing the time chitchatting with the attendant
We get it; you are trying to be friendly – just not at the drive-through!
It is discourteous to idle at the window, smiling and passing banter back and forth with the attendant when many more people are on the line waiting to make their order. Get on with it!
9. Playing music loudly
Again, make things fast and comfortable at the drive-through. Lower your music when it is your turn so the attendant can hear you.
10. Splitting the check between car passengers
A drive-through is not the place to grab a quick lunch with friends and, most notably, not when you are paying separately. Presenting different cards to the order-taker will surely slow down the line, so it is advisable that you all walk into the restaurant and order takeouts.