As a developer based in Norway, one fairly major drawback to YAML is the way that it processes the language code for Norwegian ("no").
For example: Stripe uses constants for types of tax registration numbers (VAT/GST/TIN, etc.). So there is EU_VAT for European VAT numbers, US_TIN for US tax identification numbers, etc. But what value to use for tax-exempt organisations that don't have a tax number? Well... guess how I found out about NO_VAT...
On the bright side, I did learn that way that although Norway is in the Schengen zone, apparently they are not part of the EU (hence the separation of EU_VAT and NO_VAT). I guess the 'no' name collision has taught many developers something about Norway :-)
It would be better to delete your comment so nobody else has to has to ever have this crisis.