What's up with the Drive-thru convenience stores?

Lazy?  In a hurry?  Alcoholic?  I'm curious to know the 'real' reason why drive-thru convenience stores were invented.  I have a sneaky suspision that alcohol is the first and foremost item on the store manager's inventory checklist.  With names such as Brew Thru and Beer Barn, it makes me wonder...

I found this interesting website that highlights photos of drive-thru stores throughout America... http://www.beerbarns.com/

I was 18 years old when I had my first experience with a drive-thru store.  I was visiting friends in unknown territory in Chillicothe, Ohio.  I was driving and the passenger was a native of Ohio.  We had driven up from Virginia Beach.  While driving down a main street, I was told to turn right.  Right into a building!  I hesitated, put my foot on the brake, and said "do you think I'm a freakin' idiot?  I'm not driving straight through that building!"  Needless to say, it took quite a bit more convincing but I eventually drove through.

We recently visited Warren, Ohio to attend a friend's wedding and the faint memories of my drive-thru experience came rushing back when I saw this: