Most teams that are trying to work in the agile way have taken the approach of following a published methodology (or one taught them by a vendor or consultant) more-or-less by the book. When the standard process they are using doesn't happen to fit their circumstances, they struggle with following the particular practices, rituals, or ceremonies mandated by the formal methodology they are using. It is as if they believe they are not "allowed" to change anything.
To me, this illustrates a basic misunderstanding of agile development. The defining document of the agile movement, the Agile Manifesto, quite intentionally remains silent about specific process frameworks and methodologies. Instead, it states four basic values and twelve supporting principles. People interested in applying these ideas to their work are expected to craft a process that works in their circumstances, using the values and principles as a guide.
This post tells of two team and two projects at the same company in which agile values and principles were adapted appropriately to different situations. This is what "agile" software development is all about.