Cats are most afraid of things with strong, pungent smells, such as floral water, perfume, and mentholatum. These are things kittens don't really like. Of course, what kittens fear most is water. Once they fall into the water, you'll see their paws paddling frantically, trying to climb ashore immediately.
In fact, many cats are quite afraid of strangers in the house. They become very restrained and uncomfortable, and their usual playtime disappears. Getting a cat used to strangers requires time, patience, and repeated contact from the owner. The best way to win a cat's heart is not to initiate contact.
