You’re presuming people are paying attention to everything all of the time, which they don’t. Humans need that extra level of redundancy to mitigate our own shortcomings. Also, we look twice right as well! Once while standing still, the second time instinctively when you’re already crossing in case something changed. Would you be required to do this 100% of the time? Probably not, but learning from a young age you can’t trust one look is good practice in more ways than one.

Rip Kari’s integrity

Luffy wants a stocked fridge, to honour his friendships and to be king of the pirates. He just doesn’t give a single fuck about anything else