[avmich]

Programming is both an art and a science. Art here means we don't have a hard scientific recommendations for all important cases; we have to learn tricks of the trade and use subjective judgement; naturally our programs differ widely.

Art - as something subjective - also means opinions differ on difficulty and slowness. That's perhaps why downvotes - the statement like this presented as an objective fact draws enough scepticism from those who have different experience in the subject.