I don’t use this one, because I remember when long, long ago it was in some random IP address block belonging to someone, and this particular address didn’t reply to ping.

Likely for good reason, even back then there would have bound to be lots of misconfigured endpoints trying to access 1.1.1.1, so just blocking it at the earliest point possible kept at lot of the annoyance away. Nowadays, it’s an anycast address, so it’s slightly less bad.

But for me, old habits die hard.