There is a small sub shop around the corner from my work where I get lunch every once in a while. They sell this huge hot dog which they serve on a small sub roll.
I ordered a hot dog with mustard and relish and a few minutes later I overhear this exchange from behind the grill...
CG1: Woman who took my order and went behind the grill to cook it since it was slow
CG2: Woman who is stationed behind the grill
CG1: Where is my hot dog roll?
CG2: What do you mean?
CG1: I had a roll prepped for this hot dog. It had mustard and relish on it.
CG2: .......you mean.....that WASN'T for the small steak and cheese?
For a week I was picturing this poor guys face when he opens (or worse bites into) his steak and cheese and finds it liberally coated with mustard and relish!
Here are a couple more quick sub screw-ups.
Once an old girlfriend ordered an italian with everything but hot peppers. What did she get? An italian with NOTHING BUT hot peppers of course.
Personally I like hot peppers on an italian. At a Papa Gino's years ago I made sure that I mentioned extra hot peppers when I gave my order (I was in the store so I saw her hit the key). I got a sub that literally had about a pound of hot peppers over the top of it. I was pissed and I was going to bring it up and ask what the fucking joke was when I noticed the order slip...apparently the key she hit had stuck since across the bottom was listed, "HOT PEPPERS..HOT PEPPERS..HOT PEPPERS..HOT PEPPERS..HOT PEPPERS". \
I laughed and scraped most of the hot peppers off the sub.