I've read Alan J. Perlis's epigrams a dozen of times. Some of them I don't understand. Others, highly resonate with me.
One of my favourite epigrams must be number 10 in the linked article, and in particular, the second half:
“[...] The only difference(!) between Shakespeare and you was the size of his idiom list - not the size of his vocabulary.”
I really like this idea because if you think about Python, for example, there is a finite and fairly small number of built-in functions. However, the ways in which you can combine them are orders of magnitude larger, and the more you try to combine the built-ins, the syntactic features of the language, and the modules, the more expressive your code becomes.
That is how I feel about my favourite line of code:
sum(predicate(value) for value in iterable)A fairly simple line of code that combines the built-in sum, duck typing, and a generator expression.
When you put the three together, you get an idiom that counts how many elements of the given iterable satisfy the given predicate.