There are only two hard things in Computer Science: cache invalidation and naming things.

-- Phil Karlton

You forgot the "and off by one errors"

I would add also hearing this quip every time either of those things come up un conversation.

I've always wondered if he meant coming up with good names or if he meant ensuring that names, however they're chosen, reliably resolve to the named thing.

“There are only two hard things in computer science. Cache invalidation, naming things, and off-by-one errors.”

You forgot "Off by one errors."