Employee motivation is not the opposite of dissatisfaction, they are driven by totally different factors.
In this great HBR article, Frederick Herzberg explains the reasons behind motivation, on the light of the motivation-hygiene theory of job attitudes, supported by real world examples.
In a nutshell: “If you have employees on a job, use them. If you can’t use them on the job, get rid of them, either via automation or by selecting someone with lesser ability. If you can’t use them and you can’t get rid of them, you will have a motivation problem.”