One of the best things about Japan is the way a foreign visitor will generally never have to feel fear about anything, as you’ll generally be safe no matter where you find yourself, though I did manage to find an exception to this rule. I’m a big fan of public baths and hot springs, and I learned early on that you can travel around Japan cheaply by staying at “saunas,” which are 24-hour public baths that also offer traditional saunas as well as a communal room for customers to sleep in. They’re cheap, costing around $35 to stay in the heart of a large city, and it can be fun to strike up conversations with the other patrons, who are often so surprised to see a gaijin in a place like that that they’ll buy you a beer. The first time I went to Kyoto, I thought it’d be fun to stay in a sauna, but I hadn’t realized at the time that Kyoto is a hotbed of yakuza, and the sauna I’d decided to stay at was filled to the brim with scary-looking gangsters with full-body tattoos and various scars. I tried to make the best of the situation, pretending not to notice the sideways looks I was getting while I enjoyed the baths. It was easy to pick out which man was the oyabun (yakuza boss), since he was the one getting his back washed vigorously by his underlings (kobun), who fell over themselves to do anything he wanted.
Note, the yakuza you see in saunas almost never look like this.