Drive Thrus

So, two of the last three times I've gone to a Drive Thru starbucks defeated the purpose of a Drive-Thru starbucks. I walked in, bought what I wanted, and walked out. Funny cuz I keep saying how I'd like a Drive-Thru Starbucks here in L.A. Yet, there's this one by this place I take my mom every week. and the last two times I went there, I walked through, not drove through. Makes any sense? And the one time I did go throug hte drive-thru and ordered something, we didn't even have to pay! The guy just said he'd give it to us.