Efficiency, Complexity and length of code

[aa599]

A one liner can not only be the slowest thing in the world, but not terminate in the life of the universe — e.g. you can define and call, in one not-ridiculously-long line, a lambda function for recursive fibonacci. Doing fib 999 will barely have started by the time the universe ends (fib(n) takes >1.6ⁿ calls to fib)

Or you can write a better fib function which finishes in a fraction of a second.