It's what you see in many photos of men during or after a battle, they have an eerie look in their eyes, that they are looking through you not at you.

"The thousand-yard stare or two-thousand-yard stare is a phrase coined to describe the limp, blank, unfocused gaze of a battle-weary soldier."

https://en.wikipedia.org/wiki/Thousand-yard_stare

What is the "thousand language stare"?

It's that "I've seen some shit" look -- a kind of world-weary daze of someone who has been through a few business cycles, several verses of the "this new language/paradigm/whatever will solve all our problems" song.

It's the look of someone learning yet another "teh shiny" just to stay current -- with full knowledge that it's yet another idea from the 1970s, repackaged to appeal to a modern audience.

The look of someone who simply lacks the energy to resist the zeitgeist. Who has to listen to everybody oozing religious zeal over the flavor of the week.

The look of someone who is thinking "cool, monads -- now can we roll up our sleeves and ship this product? Remember our product? We get paid for shipping product"

Read the question.