The worst one I do is my sister’s NB spouse. I knew them for decades before they realized they were NB and let us know, and I screw it up with them all the time. It’s not because I don’t support them. It’s because I don’t see anything different about them. They’re still family and they make my sister and their son happy.
We still nerd out over the same stuff and and our relationship hasn’t really changed at all. So I slip and refer to them as “him.” I think sometimes that my love for them and who they’ve always been has in a way blinded me to the outward change.
Sometimes re-wiring a house or building isn’t as practical as setting up a mesh network that’s good-enough.