Why do some people with poor orbital bones have tear troughs while others have eye bags?

They eyelid and cheek skin attach to the skin through a variety of different attachment ligaments and septa. The face has multiple fat compartments that help shape the face and these are divided by septal layers. As the face ages many people will get deflation in the upper cheek compartments and bulging of the lower lid as the septum becomes more weak. The difference in individuals is related to a combination of how their facial fat compartments age and how their septa and ligaments sag or stay tight over time.