If a restaurant like a sandwich shop ran out of bread would you get mad and make a complaint to the manager?

They don't spend hours making bread, they buy it in.

depending on the product...sometimes a restaurant can work around a problem.  When i was little, they ran out of ketchup and straws.  There was a mini mart 2 stores down, an intelligent manager would have gone over and bought what they needed.

more recently, a italian buffet place ran out of bread in a mall food court...there was a panera next to them with plenty of bread....as the manager of the italian place, I would have credited customers with the cost of a roll at panera (when they bought a combo meal that came with bread).

but neither time did a manager trouble shoot the situation..

if this is something like subway where they have their own bread recipe, you can't just go buy bread elsewhere though