Spending time optimizing a program that you will use once is a waste. Sitting idle while waiting for a program to finish is also a waste. So I think it's reason

Spending time optimizing a program that you will use once is a waste. Sitting idle while waiting for a program to finish is also a waste. So I think it's reasonable to optimize for programmer time the first time, and then re-visit the design if you discover the code is getting reused and fed larger data sets.