Most things don't matter.
Do you remember my post last week about "quiet" Agile and why I worry that some agile practices put introverted people off Agile?
It doesn't matter.
Most things in Agile don't matter.
But a few do.
Here's the one thing that matters most: Principle 1 of the Agile Manifesto, "Our highest priority is to satisfy the customer through early and continuous delivery of valuable software."
Just about everything else is detail or opinion.