I believe in drive thru etiquette - here it is:

If you are in a hurry and are ordering for yourself - use the drive thru...
If you have one child in the car and strapped to a baby seat - use the drive thru...
If you are picking up orders for the entire soccer team, go inside. Or at least, know your order before pulling up to the order box if you can't find another parent to watch the kids...
If you are a single and don't have a clue what you want and have to ask alot of questions - please go inside!
If the entire office has asked you to pick up orders, go inside, please!

Also - Drink Station Etiquette: Get in get out. Do not stand around and talk to your friends. Do not sip and fill, sip and fill, sip and fill. Do not let your children play with the machine - get it for them! Fill the cup and then move to the side to add the cover and straw, get out of the way for gosh sakes!!!!

One of my major peeves is the person who think they are the only one in the world and no one is behind them and in a rush. Sorry, I won't be polite to you!