If you start working at 8am, your whole day is going to be interrupted with impromptu meetings and emails. If you start at 6am, you only get 2-3 hours uninterrupted. If you've been writing software for a while you learn that the interruptions are intentional and are about control. When people see a software engineer working without their help, it is troubling for them. It means the problem can be solved without them, hence interruptions. Most non-developers actually have family lives and start getting calls from their spouses about 4:30PM. By five they're gone and work can proceed.