Why do many people dislike getting up early?

I think the main reason people dislike waking up early is simply because it disrupts their natural sleep cycle. Our bodies are wired to follow certain rhythms, and forcing yourself up before you're fully rested can leave you feeling groggy all morning. For example, when I was training for that half marathon I mentioned earlier, those 5 AM wake-up calls were brutal - even though I knew I had to do it, my body just wasn't cooperating those first few weeks. That being said, some people in Shanghai actually prefer early starts because the city is quieter before the rush hour chaos begins.