“We really need to do this!” “This is super important!” “Why haven't this been completed yet?” The life of a team in an organization is not always a walk in the park. In a complex world several things need to be solved at the same time and the value is often not possible to predict beforehand. The person with the immediate need will of course know, but from his/her perspective only and that will not help the team.
So, what to do?
You need intensive communication between team and stakeholders in order to get a shared view, acceptance and understanding on priority.
Easy right?
Well, maybe not so easy. Communication is central in agile but even if you put your full energy into this it will still only work up to a point, sometimes even the best communication turns into a too high cost for the team. If you spend all time discussing prioritization and doing refinement in order to understand the cost of multiple competing needs the team will have too little time to realize the value and then this is waste. At this point the team will probably start to talk about kanban. They feel that everything is in a stand stil and want to get things done, let’s get a flow going. This could be a good enough, you will start to get things flowing through and yes a lot of the things will be the "loudest”-requirements but some of the actual value deliveries will slip through.
But if you really want to fix the problem you must deal with something much harder, dependencies.. If the team is not able to realize value more or less by themselves and instead has high dependencies to other teams, managers or architects, processes you name it you will start to build a prioritization chaos.