I think these questions are often really about solutions that are "efficient" from the standpoint of laziness and impatience, not runtime.

Questions about Perl idioms and some golfing exercises are examples of this kind of thing: "I know this works, but there must be a shorter/easier way".

Somtimes, that happens to be the same thing as efficiency from a machine perspective (e.g. using map and grep instead of looping over things again and again), but it doesn't have to be to still be valuable.