Im writing an Agile course for some of the new guys we are on-boarding recently and I want to add a cautionary tale so they understand that Agile is not meant for all projects. My problem is that because of the nature of the projects I work in Agile has worked pretty well so far so I can't honestly point out what can go wrong and why when you use it in the wrong kind of project.

Does anyone have a good real life example of a project where an Agile approach (e.g. Scurm) simply didn't worked out?