These posts do, in fact, write themselves

Client: What’s your e-mail address?
Me: npamby@myfirm.com
Client: I wasn’t ready
Me: npamby. At. Myfirm, that’s all one word Dot Com.
Client: M?
Me: N as in Namby.
Client: N. P. A… what’s the rest?
Me: M. B. Y.
Client: Ok.
Me: Ampersand, you know the At sign?
Client: At.
Me: MYFIRM
Client: All one word?
Me: All one word.
Client: m.y.f.i.m.
Me: No, it’s Myfirm. M.Y.F.I.R.M Dot Com
Client: Dot what?
Me: Dot Com
Client: Oh…I didn’t have that when I was sending you an e-mail
Me: Have what?
Client: The Dot Com.
Me: You definitely need that
Client: npamby@myfirm, right?
Me: You can just use the regular mail if you want to.
--

Update: I'm glad to see that the client was not the only genius involved in this call. Ampersand...at sign...same-same. or not.