Let's imagine that through the application of advanced biotechnology and cybernetics, humans in the 23rd century have created a sort of machine mitochondria that lives inside a person's cells and codes for the natural growth of artificial structures in the body. People are born with these machines already living inside them (again, much like mitochondria) and because of them, radical body-modding has become possible, creating a wide variety of morphological subcultures and clades of humans living in orbital habitats around Earth and Mars (for a deeper explanation and exploration of these theoretical concepts, watch Isaac Arthur's video on Bioforming & Gene-Tailoring on Youtube).
These 23rd century men and women may be born with or develop naturally as they grow such amazing abilities and adaptations like biometal claws and fangs, bones laced with graphene, eyes that can see wavelengths never meant for human eyes, extra ATP or denser (maybe even synthetic) muscle tissue, and even complex telepathic neural implants that communicate via radio waves and are grown from a person's own tissue. Some may choose to become even stranger, further modifying their bodies and their genes to incorporate features like fur and scales, and various natural weapons like venom glands or a secreted poison. But for some reason, a lot of people just want to be taller.
Why is this? What reasons would someone have to want to be eight or ten feet tall (assuming our mastery over the new flesh has allowed us to circumvent the limitations placed on people who are born today with conditions that cause abnormal height)? Are any of them practical? Or is wanting to be a giant strictly a confidence booster or intimidation tactic?