It may sound extremely strange to do, but you should always make sure to have extra cat Food on you at all times while playing Yakuza 6. This is because one of the first side quests you will be given involves an owner of a failed cat cafe needing you to bring him as many cats off the streets as of Kamurocho City as you possibly can. In order to do this, however, you will need cat food. Unfortunately, most of the cats you find won't be so easily pleased, with most of them needing several cans of cat food before won over and heading to the cafe.
You will be able to find stray cats just about anywhere, but they usually tend to randomly appear in both streets and alleys. Because of the randomness of it all, you will never know when you will need a handy can of cat Food. On top of this, you can only purchase cat food at select grocery stores, so it's suggested you stock up on them both early and heavily. This will prevent you from having to make repeat impromptu trips to said stores whenever on of these felines makes a sudden appearance.
Need help finding all the stray cats? Check out our Guide on How To Find Every Stray Cat In Yakuza 6!