I learned this the hard way. I have been training a bunch of 5-10 years experience tech-leads, architects, and what not. But on the job, I realized quite a lot cannot switch context and subject at all.

I've found people who have spent decades on one topic in a very specific vertical. It is amazing how they know EVERYTHING in that and I can listen with my jaws dropped to the floor for hours. Then I will wake up, with that spine-chilling shake all over my body on how patient and dedicated one has to be to be on that straight line their entire life.