If the question is about the graduation project, the student usually faces a lack of understanding of the project idea, which is usually determined by a small specific problem that needs to be resolved through what the student learned during his initial study.
Most of the problems encountered the student during the implementation of the project and writing is limited to the lack of communication between the student and the supervisor, and as a result does not know how to start writing the project and how it ends. It's the same problem as Master's students. So I think that the student often suffers a lot in order to get the graduation project acceptable to himself and others.