If you look at the core elements of Scrum as described by the Scrum Guide, Scrum isn’t all that difficult to learn. However, it is very difficult to master. Many teams that I have worked on various projects feel so comfortable with Scrum that they believe they do not need to follow the events, despite the founders of Scrum stating explicitly that:
“Scrum’s roles, events, artifacts, and rules are immutable and although implementing only parts of Scrum is possible, the result is not Scrum. Scrum exists only in its entirety and functions well as a container for other techniques, methodologies, and practices.” [Scrum Guide, 2017; Sutherland/Schwaber]
Why teams choose to tailor Scrum is a discussion for another time. Based on my experience working with teams, the Retrospective seems to be the first event to be eliminated when things aren't going well.
Reason 1: Very few Scrum Masters receive the proper Scrum training. Most Scrum Masters who I coached have never attended any formal training; they learn by observing or by practicing “on the job”. Without proper knowledge of how to run a Retrospective, this event usually turns into a big waste of time for the team.
Reason 2: As a result of poorly executed Retrospectives, Scrum teams treat this as a project “post-mortem” or “lessons learned” in which the project team members vent and/or complain about things that didn’t go well and take no steps to resolve the issues.
Reason 3: Lack of perceived value encourages the team to abandon the Retrospective, which removes this critical opportunity for the team to learn from its mistakes and seek opportunities to get better together. Eliminating this key activity will typically destroy the team’s ability to get better.
A truly high-performing Scrum team is something that very few practitioners will ever experience. A team can only achieve this status if it develops a culture of continuous and relentless improvement, which requires self-reflection and adaptation. Without the Retrospective, the team will not be able to regular examine how things are going.
In closing, if you are satisfied with your team’s current state and with status quo, perhaps the value of the Sprint Retrospective is not high for you. However, I have a feeling that this investment in time outweighs the cost of decreasing team morale.