Lifehack BS: Speak in a Lower Pitch to Boost Your Confidence
Lifehacker points to this study which says that by faking a lower voice you exude confidence and power.
Lowering the pitch of your voice could come in handy when dealing with customer service, authority figures, or when giving a presentation.
Or you could get better success with customer service by not being a dick and ace your presentation by knowing your material and practicing a lot.