The primary difference between simple and easy are decisions. A good senior will spend more energy on considerations for appropriate decisions than the actual work.
This is surprisingly often not understood, even by people I showed the video. And I am not sure why.
But I do think it's necessary in out field to start understanding this much more deeply, especially for senior engineers.
For e.g. - for production deployment, I could either put the entire office upside down. Fires across the departments. Broken applications. Rollbacks. Or, I can automate all of our QA test cases and have a one-click deployment. No huss or fuss. I'm sure after having this experience, someone will definitely say - well, this was easy.
Anyway, good discussion.
I like to state it as complex vs. difficult.
Finding a bug in ten thousand lines of crappy VB code code is 'difficult', but not fun.
Writing an space/time efficient implementation of level set topology optimization is complex.
Senior developers usually love complex problems, but hate merely difficult problems.