Barry Overeem wrote a list of common pitfalls in Scrum, you might recognize (a few)  in them.
Today, the one resonating with me is this one:

Demonstrating the results to the Product Owner, instead to the stakeholders

We can definitely improve on that one!

http://www.barryovereem.com/the-5-most-common-pitfalls-of-the-scrum-events/