Light fixture wiring - black to black, or white to black?
An Edison bulb has a metal &quot;tip&quot; that is totally inaccessible once you start screwing it in.  It does not make contact with the socket until it's screwed all the way in.
It also has an outer metal threaded screw base, which is easily touched while screwing it in.  It makes contact with the sockets &quot;shell&quot; immediately and continuously while screwing it in.
The socket's shell is attached to the white wire.  If you connect that to neutral, then touching a bulb's socket while screwing it in will be harmless unless there's a wiring fault.
Of course if  you connect the socket shell to hot, then if you forgot to turn the switch off, you can get nailed by your finger touching the shell as you screw it in.