Congratulations on your success! However, the ITIL Foundations certification demonstrates that you have base-level knowledge of the concepts of IT Service Management. One of the challenges that the authors of ITIL faced when writing such a complex topic, is how to structure ITSM so that people could learn the topic in a series of progressing classes instead of all at once.
The Service Lifecycle that you learned in the ITIL Foundations class is the first step in the progression of courses in IT Service Management. As such, the ITIL Foundations class simplifies the complex topics of IT Service Management into a few-day course with an exam at the end. There is no way that 1000+ pages of the IT Infrastructure Library can be learned in a few days. This simplified view of IT Service Management does not provide the necessary guidance to truly reap the benefits of what ITIL can offer an organization.
In the intermediate courses, the Service Lifecycle is explored in far more detail. This detail often conflicts with the simple concepts learned in the ITIL Foundations class as these concepts are explored and a full understanding of the concepts is gained.
An interesting side effect of continuing the intermediate and advanced courses is that students come away from the course realizing just how much they didn't know before the course and how much ITIL Foundations left out.