Don't confuse premature pessimization for the warnings against premature optimization.

I can write bubble sort, it is simple and I have confidence it will work. I wrote quicksort for class once - I turned in something that mostly worked but there were bugs I couldn't fix in time (but I could if I spent more time - I think...)

However writing bubble sort is wrong because any good language has a sort in the standard library (likely timsort or something else than quicksort in the real world)