I have been scrum master for a team for about half a year. Up until the last month, we never really took the sprint goal seriously, but after reading a little more we are starting to (with pretty good effects).
When studying up on this, I found conflicting views on whether a sprint goal is mandatory or not. Primarily this article which is posted on scrum.inc: https://www.scrum.org/resources/blog/why-sprint-goal-not-essential-mandatory-artifact