its not just fast food that sucks.  I check each and every order I get for any kind of take out now.  I have had Denny's, Ihop, mexican, chinese, italian, burger, fish and pretty much about every fast food establishement mess my order up at one time or another.
Yes - I eat out far too often.  the few places that have never messed up - I still check their orders too.  Its not a matter of if they will mess up - its a matter of when will they mess up.  Some times it works out for you too.  
One time i got an extra order of prawns at my chinese place.  I love prawns - But I still called them to notify them someone did not get what they expected.  I would have returned the prawns if they had wanted me too - I did ask.
anyway - you want to be sure your food is right, do it your self.
as far as waiting - I have been asked to wait many times.  I generally do it.  But you know - i get asked too often and I think i may need to start refusing to go out front and wait.  If you cant get my food to me without making me wait out front - maybe you should just refund my money.
makes sense to me - and always check your order.