The developers don’t get along with the test team, so they don’t work closely with them. The developers do all their work and then throw it over the fence to the testers.
The designers think the developers are jerks, so they never ask for feedback. They send them docs when they’re finished.
Maybe the devs hate the DBAs. Or the UX team thinks the product owners don’t know what they’re talking about.
When functional silos form, feedback loops get longer. Effort is wasted. Or worse: Sometimes technical or creative decisions are actually driven by avoidance of people problems. That’s profoundly dysfunctional.
