The quality of the fries is directly proportional to how good the attendant at the fries station is at following procedure and not dumping loads of pre baked fries in the keep-warm bin (don't know the English McD's phrase for it). They get worse from being under the heating lamp for too long or being left over the frying pan too long dripping. It's not rocket science but many don't want to be shouted at when the station runs out of fries so they overdo it on the supply. This is exaggerated when a rush is winding down and the production isn't scaled down quickly enough.

If I remember correctly there is a small trouble shooting section in the floor managers quality guide (small booklet with all procedures, weights, temperatures, stack height of boxes etc) which hints you at what is going wrong if you ever want to know and get your hands on one. Though that will have changed since mine is ancient.

I figured as much, and I would expect a Japanese mcdonalds employee to give slightly more of a shit than say, an American employee so that probably explains the discrepancy in the average experience if you were to compare them.

That reminds me of when I worked at a movie theater. We used to serve the popcorn scooped directly from the popping machine into a bucket. But then they had a corporate guy come in and install warmers so we could pre-load a bunch of buckets/bags of popcorn and hand them out when ordered. Of course the ones from the warmers aren't as good as the ones freshly popped, and this guy gave some bullshit about "ackshually popcorn right out of the popper isn't as good, it needs time to dry". It's not like the customer is about to take their popcorn into a multi-hour sitting activity where they have time to "let it dry"...

I always tried to hook up the nice customers with the fresh stuff when I could, it felt criminal handing them one out of the warmer.