There is also the fact that an IPv6 IP has a maximum and minimum number of characters and separators, but not a set one, so the length of any given address is variable.

Instead of being able to run a groove in my head mentally, and read with any sort of rhythm, I have to read them like binary bytes. Every address feels like a foreign phone number where your normal rhythm doesn't fit, but it never gets better.

Perhaps, IMO, the greatest and only sin of IPv6. That and using fucking colons.