The following is a quite comprehensive list of attitudes and skills that contribute to being a great Scrum Master; of course you don’t have to meet this entire list to be a great Scrum Master; consider it as some inspiration on areas you might want to RESEARCH. 

• Involves the team with setting up the process. A great Scrum Master ensures the entire team supports the implemented Scrum process.
• Understands team development. A great Scrum Master is aware of the different phases a team will go through when working as a team. He/she understands Tuckman’s different stages of team development: forming, storming, norming, performing and adjourning.
• Understands principles are more important than practices. Without a solid, supported understanding of the agile principles, every implemented practice is basically useless.
• Recognizes and acts on team conflict. A great Scrum Master has read the book ‘The 5 Dysfunctions of a Team’ by Patrick Lencioni. He/she therefore recognises team conflict in an early stage, can apply different activities to resolve it, and even better, he/she knows how to prevent conflict.
• Dares to be disruptive. A great Scrum Master understands some changes will only occur by being disruptive. He/she knows when it’s necessary and is capable to be disruptive enough to enforce a change, but without causing irreparable damage.
• Is both dispensable and wanted. A great Scrum Master has supported the growth of teams in such a manner they don’t need him/her anymore on daily basis. But due to his/her proven contribution he/she will get asked for advice frequently.
• Let the team fail (occasionally). A great Scrum Master knows when to prevent the team from failing but also understands when he/she should not prevent it. The lessons learned after a mistake might be more valuable than some good advice beforehand.
• Encourages ownership. A great Scrum Master encourages and coaches the team to take ownership of their process, task wall and environment.
• Has read… A great Scrum Master has read all the stuff produced by e.g. Geoff Watts, Lyssa Adkins, Tobias Mayer, Henrik Kniberg and Gunther Verheyen. 
• Has studied… A great Scrum Master has studied the Trello board that Growing Agile has published. The Shu-Ha-Ri levels offer a very useful STRUCTURE to a knowledge base for every Scrum Master.
• Is RE-TRAINED. A great Scrum Master recognizes himself in the acronym made up by Geoff Watts, RE-TRAINED: 
  • Resourceful: is creative in REMOVING impediments
  • Enabling: is passionate about helping others
  • Tactful: is diplomacy personified
  • Respected: has a reputation for integrity
  • Alternative: is prepared to promote a counter-culture
  • Inspiring: generates enthusiasm and energy in others
  • Nurturing: enjoys helping teams and individuals develop and grow
  • Empathic: is sensitive to those around them
  • Disruptive: breaks the STATUS quo, help create a new way of working
• Has faith in self-organization. A great Scrum Master understands the power of a self-organizing team.  Attributes of self-organizing teams are that employees reduce their dependency on management and increase ownership of the work. 
• Values rhythm. A great Scrum Master understands the value of a steady Sprint rhythm and does everything to create and maintain it. The Sprint rhythm should become the team’s heartbeat, which doesn’t cost any energy. Everyone knows the date, time and purpose of every Scrum event. 
• Knows the power of silence. A great Scrum Master knows how to truly listen and is comfortable with silence. He/she is aware of the three levels of listening and knows how to use them.
• Observes. A great Scrum Master observes his team with their daily activities. He/she does not have an active role within every session; for example, the daily Scrum is done by the team itself.
• Share experiences. Great Scrum Masters share experiences with peers. This might be within the organisation, but also seminars and conferences are a great way to share experiences and gather knowledge. 
• Has a backpack full of different retrospective formats. A great Scrum Master can apply lots of different retrospective formats. This ensures the retrospective will be a fun and useful event for the team. He knows what format is most suitable given the team’s situation.
• Can coach professionally. A great Scrum Master understands the power of professional coaching and has mastered this area of study. Books like Coaching Agile Teams and Co-Active Coaching don’t have any secrets for him/her. He/she knows how to guide without prescribing. 
• Has influence at an organizational level. A great Scrum Master knows how to motivate and influence at tactical and strategic levels.  Some of the most difficult impediments a team will face occur at these levels, therefore it’s important a Scrum Master knows how to act at the different levels within an organization.
• Prevent impediments. A great Scrum Master not only resolves impediments, but he also prevents them. 
• Isn’t noticed. A great Scrum Master isn’t always actively present. He/she doesn’t disturb the team unnecessary and supports the team in getting into the desired ‘flow’. But when the team needs him/her, he/she is always directly available.
• Forms a great duo with the Product Owner. A great Scrum Master has an outstanding partnership with the Product Owner. Although their interest are different, the Product Owner ‘pushes’ the team, the Scrum Master protects the team. 
• Allows leadership to thrive. A great Scrum Master allows leadership within the team to thrive and sees this as a success of their coaching style. They believe in the motto “leadership isn’t just a title, it’s an attitude”; it’s an attitude everyone in the team can apply.
• Is familiar with gamification. A great Scrum Master is able to use the concepts of game thinking and game mechanics to engage users in solving problems and increase users’ contribution.
• Understands there is more than just Scrum. A great Scrum Master is also competent with XP, Kanban, and Lean. He/she knows the strengths, weaknesses, opportunities, and risks of every method/framework/principle and how & when to use them. 
• Leads by example. A great Scrum Master is someone that team members want to follow. He/she does this by inspiring them to unleash their inner potential and showing them the desired behavior
• Is a born facilitator. A great Scrum Master has FACILITATION as his/her second nature.