개구리 올챙이 적 생각 못 한다
gaeguri olchaengi jeok saenggak motanda · The frog doesn't remember being a tadpole.
People who've made it forget how they once struggled.
When to useA senior who's hard on newcomers despite starting out the same way.
Examples
본인도 첫날 길 잃었으면서 신입한테 뭐라 하네. 개구리 올챙이 적 생각 못 한다니까.
He got lost on his first day too, and now he scolds the new hire. The frog forgets the tadpole.