Is learning C really a must for a programmer?

Many have this opinion. Somehow, by doing manual memory management allocation and garbage mangement one would become a better programmer.

I have little experience in C mainly because I can write terser and more readable code in Racket or Haskell. However I'm willing to give C a try just to learn these lessons that everybody keeps talking.

But I have a sneaking suspicion that I already know most of what is there to know. Can you list some useful lessons that a typical high level code dweller would be oblivious of?

>>35
Knuth's quote is about premature optimisation, but optimisation is never premature, so it's like saying "if the moon is made of cheese, it must be cheddar".

Have you read through the entire TeX source code? I bet a lot of programmers today would say that the entire thing is "premature optimisation" and a TDWTF. If I remember correctly, there isn't a single instance of dynamic allocation, it's one huge monolithic application.