One Sad Dog can Infect a group of 100

Hire/Promote those with ... Sunny Dispositions.
Fire those with perpetually ... Gloomy Dispositions.

(Hint: The farther Up the Organization you go, the more important this gets.)
(Rule: Leaders are not permitted to have “bad days” ... especially on Bad Days!)
(Rule: One Sad Dog can Infect a group of 100.)

Source: Tom Peters