From the Hibernate documentation:
"Alternatively, we could use a non-lazy collection or association, by specifying lazy="false" for the association mapping. However, it is intended that lazy initialization be used for almost all collections and associations. If you define too many non-lazy associations in your object model, Hibernate will end up needing to fetch the entire database into memory in every transaction!"
In short, you don't want to load the entire DB by accident through a chain of associations
Hope that helps!