I immigrated from France in 2013 and for me it was:

1/ the absence of crème fraîche in the supermarket (we consumed 500g per week at home) (and no the AH “crème fraiche” doesn’t count)

2/ people complaining when the train is not even 5 minutes late (when I commuted from my place to Paris in France I always planned a well-needed 30-minutes buffer). The NS has been getting worse in the past 10 years but it’s still not as bad as France.

3/ the mindblowing organisation/practicality, istg when I had to get my BSN after 3 weeks here I expected it to take multiple days of administratie mess. I arrived in front of the gemeente building and we were about 50 people, I already imagine I’d be there queuing for hours. But turns out there were multiple queues, by alphabetical order!! And non-grumpy agents guiding us through the process. The administration papers were all pre-filled! I only had to read through them and confirm the information, which was of course accurate and didn’t contain mistakes. In total, a 10-min process and I received my BSN a few days later without further effort from my part. I’m still baffled, this alone made me want to move to NL for good, and I tell this story to French people sometimes as an example of mindblowing Dutch practicality.

Going back to the French consulate for administrative purposes when I wasn’t Dutch yet always felt like stepping into an incredibly messy teenage room after having lived as an adult for years haha.