[FullMtlAlcoholc]

I think what your mentor meant was don't be bored. I have some misgivings about this advice though as I think it should be more nuanced. It's ok to be bored. With all the gifts modern society has given us, one of the costs has been over-stimulation.

When I'm bored, my mind is clear of any extracurricular thoughts or ideas, and I come up with creative solutions to the “problem” of being bored. One of my hobbies is distance running and it bores me. But almost all of my great ideas have come to me while running. I'm free from the weight and worries of the world

According to two studies detailed in Harvard Business Review, focusing on a mundane task allows your brain to “daydream” and ultimately boosts creativity and problem-solving afterward. Essentially, part of your subconscious mind will start working on things that have not been at the forefront. Your mind is literally reorganizing and optimizing its structure, creating new connections between neurons. [1]

When I've been banging my head against the wall trying to solve some technical problem, I go for a run and forget about my stresses and worries

If people perceive you as boring when you are fulfilled with life, in the words of the Dude, "That's just like their opinion man."

1. https://hbr.org/2014/09/the-creative-benefits-of-boredom