Back in the early days of Scrum, the Scrum Master role was exciting. The days of the pigs & chickens, the days when being a Scrum Master was considered dangerous.
In those times there was the saying
a dead Scrum Master is a useless Scrum Master
And even today I still use that when selecting a Scrum Master to work with.
If you never got fired as a Scrum Master then you probably did not show enough courage to achieve breakthrough improvements.
Scrum Master as a Sheep Dog
As a Scrum Master you would work with the Product Owner on value; coach management on organizational design; and work with the Development Team on self-organization and technical excellence. The Scrum Master would strive for the team to put the product into the hands of the customer every Sprint. It was natural to work on test automation, code quality and deployment. If the Scrum Master would catch a project manager sneaking in from the back, breaking the rules and disturbing the teams, the Scrum Master would go for a frontal confrontation, or as Brian Marick once said: