What is the islamic reason behind hell, is it to instill fear or love for allah?

A lot of people talk about the love for God, where as it becomes aparent that love for Allah comes at a price, sacrifice, killings and even eye for an eye? A sharia law that is not perfect and treating of the body as if its a shameful thing to have rather than embracing it from a young age. then all these questions have answers that are dated. Change is required yet it seems people dont want change. dont want to progress as a society, as a human race....