Someone says "I'm quite vane", to which I reply "you don't look it". Am I paying them a complement or an insult?
'Intelligence' is nothing more nor less than an index of linguistic ability. The question of how much is learnt and how much is innate is therefore not just empirically unanswered but definitively unanswerable. The only innately stupid person is the one who believes that this issue comes down to biology.
"Time flies while you're having fun". As beings of very limited lifespans, it presumably makes sense to keep fun to a minimum.
Ok, so I'm not quite at Nietzsche's standard yet, but at least I'm not recommending beating up women.