My collection of project failures...I am sure there are a lot more.
So, think about whether you are doing anything to address these potential "roots of problems".
1. Wasting of resources through dedication to projects, making them unavailable to support other projects.
2. Failure of management to provide real guidance on priority of projects before they are planned and promised.
3. Failure of management to kill projects when their reason for existence goes away.
4. Insufficient identification of dependencies necessary to deliver the project.
5. Wasting of resources through underutilization because they aren't the "best resource" for the job.
6. Wasting of the "best" resources through over-utilization, multi-tasking, and burn-out.
7. Delivering original scope when conditions/needs change. OR Accepting changes to scope without sufficient analysis of impact on the project (or on other projects).
8. Resources are expected to address tasks from different projects in a coincident time-frame... multi-tasking also impacts single project durations when dedicated resources are expected to wear several hats.