The Completer Finisher worries about what might go wrong. This type of person is never at ease until until they have personally checked out every detail and made sure that everything has been done and nothing has been overlooked. It is not that they are overtly or irritatingly fussy - their obsession is an expression of anxiety.
The Completer Finisher is not an assertive member of the team, but will maintain a permanent sense of urgency which they communicate to others to galvanise them into activity. This type of person has self-control and strength of character, and is impatient of and intolerant towards the more casual and slap-happy members of the team.
If the Completer Finisher has one major preoccupation, it is order: they are a compulsive meter of deadlines and fulfiller of schedules.
If this type of person are not careful they can be a morale-lowering worrier with a depressing effect in the rest of the team, and they can too easily lose sight of the overall objective by getting bogged down in small details. Nevertheless their relentless follow-through is an important asset.