To block caller ID for a specific call, you dial *67 beforehand. Was that intended to be a mnemonic? The only reasonable abbreviations I can come up with are *[N]on [P]ersonal, *[N]o [S]ender-info, *[M]ake [P]rivate, etc. Nothing that seems like it should be the “official” meaning behind the particular choice of the number 67.

On the other hand, to unblock caller ID for a specific call (if you have your line blocked by default), you dial *82 beforehand. That could just stand for *[V]iew *[C]aller-id.

On Verizon cell phones,
# To check your voicemail: #[V]oice [M]ail.
# To check your minute usage: #[MIN]utes.
# To check your text (data) usage: #[DATA].

See, those make sense. Although it would be nice to have the phone check in the background, automatically and periodically, and update usage information internally.