I must be in my wrong mind then. :)

Just because it's a 128-bit number doesn't mean it should be difficult to remember, the standard notation goes a long way toward that. 2001:db8::cafe:f00d and fc00:bad:beef::1 aren't what I'd call the epitome of "can't remember"

Mind that real-world global addresses often have four groups of almost-random at the beginning, but it's usually not terrible to commit to memory.

Have you tried? I knew my v6 block (and static addresses within that, which is like two: router and server) back when I used v6 ten years ago, same as I know my v4 address, without really actively learning either

For sure this is a self-hoster thing, where you have pets not cattle, but so is memorizing your v4 address(es)

Who's out there remembering IPv4 addresses?

There is nothing wrong with ipv4 in the LAN, for public things in the internet DNS is and should be used anyways making ipv6 there a non issue.

Is is really so hard to remember the addresses fd::1, fd::2 etc. for your local network?

Use DNS?

2600:: is pretty handy