Normal working hours changes based on the project I'm on. I often work with people in a timezone that is 12 hours off my own. In that case one of us ends up on a 10pm call at some point. I actually prefer 7am-4pm but found that would just lead to 7-7 as "work", more likely useless meetings, usually creeps in later. Now I just start at 9.

I had a project with a company in Singapore that had me working 3am Sunday morning, almost every week. That got old, fast.