Projects frequently do not meet customer expectations for which reasons?

This could be due to several reasons and factors

1. Failure in the requirements analysis process
2. Failure to translate keystakeholder needs, desires and exepctations for formal requirements
3. Failure to fix and freeze the requirements leaving door open for requirements changes thrpughout the lifetime of the project
4. Making/Accepting compromizes here and there affecting the nature of the deliverables and sometime without concurrence from the key stakeholders
5. Failure in the test and verification process to ensure that agreed functionality/peformance considerations are really met in the project deliverable

There could be other things ,, but this is what comes directly in my mind !!