Surprise!
Personally, if I was opening a can of peas and found corn inside, I’d be relieved, but I don’t think this is what this person felt when they expected peas; they were probably feeling disappointed, and most of all, confused. The only thing we’re thinking right now is that this mistake couldn’t be a single incident, since these food cans are labeled automatically, using a machine.
This means that every can of corn that came from this line received the wrong label and was marked as peas. Would you take this product back to the store? This isn’t even their mistake, but the factory’s, and no one’s going to call the factory and complain, because no one cares enough.