When I have to discipline my hapless lackeys here at Purgatory, Inc., I like to do so in a Jacob Marley "vengeful ghost" type voice. It confuses them and keeps them nice and twitchy.

In fact, whenever I am unable to avoid speaking to them, I select from one of the following voices:

Popeye
Foghorn Leghorn
Yosemite Sam
Henry Kissinger
Carol Anne from Poltergeist