The 70 hour work week meme is quite popular on social media these days. It took me 15 years of experience to debunk the myth that I have to work 40 hours a week to be actually “productive”.
In the early part of my career, it was simpler. As a software engineer someone told what to build and you built it. More hours meant more stuff got built. But with experience I figured out that I was probably building the wrong thing or building the thing wrong. I was rebuilding more than I was building. I realised that if I could be more productive if I communicated and comprehended more things that just building them. Some time later, I learnt I am productive if I choose not to build something. I got better at trading off costs and benefits of doing things. It is okay to sometimes not do anything rather than doing something that exacts a toll on you and the company later. It is definitely better than just doing something to fill in the mandated 8 hours of work.