How to work 40 hours a week as a software engineer?

I don't understand how people can work 8 hours a day. I usually arrive to the office at 8 am, I spend 2 hours watching YouTube videos, 2 hours browsing Chambers, 2 hours playing video games, 1 hour chatting with my colleagues, 1 hour eating lunch. I spend a total of 0 hours writing code. My boss is not mad at me though, I don't understand why.