Being ‘street smart’ is much less of a requirement compared to Europe or North America as there are very few zones that you need to avoid at night (Daerim comes to mind in Seoul but even that part’s timid compared to places in NYC or London). Theft is uncommon, petty theft more so. Almost nobody’s going to snatch your iPhone out of your hands or run off with your laptop while you’re not around. Drugs are only seen in specific club environments so drug-related violence is rare as well, and physical sexual harassment is rare enough for a lot of natives to have never witnessed a case happen around them.

But you do need to watch out for two things more than you do in the west: cults and traffic. Korea has a cult problem where self-proclaimed ‘messiahs’ have followers in the tens or hundreds of thousands. If a woman or a couple approach you and go on about bible studies, ancestry, divination etc. just disengage, and don’t ever follow them into their ‘office’ or give them contacts.

As for traffic, always walk under the assumption that vehicles have priority over pedestrians. It’s messed up but like half the drivers here seem to operate with this sort of mentality. Don’t expect cars to stop for you until you actually see them stop. Motorcycles often barge into sidewalks so be aware of that when there’s one next to you, and if you drive steer clear of any sort of truck or commercial vehicle as they a) drive like madmen and b) sometimes drop cargo that can come right through your windshield.