Smelliness generally increases proportional to length, simply by virtue of the fact that it takes longer for my human brain to parse. A one line function has no

Smelliness generally increases proportional to length, simply by virtue of the fact that it takes longer for my human brain to parse. A one line function has no inherent smell because usually I can tell immediately if there's anything else smelly about it. A 250 line function smells a bit more since there are more places for more insidious smells to hide. Very short methods tend to be very easy to reason about. What properties of 100-250-line methods make them optimal?