My favourite is when they stress the importance of typing the name exactly as it appears on the passport or on a debit card, then doesn't accept my name.
This is why I don't use Namecheap anymore fwiw. They used to accept 'ø', they redesigned their interface, I had to add a new debit card to my account, their new system didn't accept 'ø' yet told me to write the name "exactly as it is on the card". Customer service just told me to write a name that's not mine in the billing info; I moved to a different registrar instead.
It's not quite the same, but every time I put my apartment number in the second address field (which is more or less exactly for apartment/duplex numbers etc), it thinks for a second and says "USPS has a suggested more accurate address" which simply appends it to the street address.
This is why I don't use Namecheap anymore fwiw. They used to accept 'ø', they redesigned their interface, I had to add a new debit card to my account, their new system didn't accept 'ø' yet told me to write the name "exactly as it is on the card". Customer service just told me to write a name that's not mine in the billing info; I moved to a different registrar instead.