It is incredibly fatiguing. Oh, you were working at a company for two years on technology X? Sorry, we need to hire someone who knows Y which you couldn't because you were working on X. No, I don't care that you could learn it in 3 days, our HR procedure says we can't give you 3 days.
Then I go download some C source code from 15 years ago and it still compiles just fine and I smile a little bit.
Then I go download some C source code from 15 years ago and it still compiles just fine and I smile a little bit.