I once was leading / coaching a team that struggled mightily to work together as a team. I was the Director of R&D at an eCommerce SaaS product company. We had been leveraging Scrum for a number of years with reasonably good success and had approximately 10 Scrum teams focusing on the various aspects of our online product.
But there were a couple of teams that were really struggling, which often seems to be the nature of things. Out of ten teams, we had about three that were high performing, three that were moderately performing, and three that struggled along. Don’t get me wrong, the team members were solid people and good employees. It was just that this whole “agile collaboration thing” was hard for some of them to grasp and embrace.