Cat behavior looks strange until you know the backstory, most of it traces back to instincts from kittenhood or the wild.

• Kneading: A leftover habit from nursing, when kittens knead their mother to encourage milk flow.
• Head-butting: Cats have scent glands on their heads and are marking you as part of their territory.
• Bringing you "gifts": Dead bugs or toys are often a leftover hunting instinct, not a gift in the human sense.
• Sitting in boxes: Small enclosed spaces feel safe and help regulate body temperature.
• Knocking things off tables: Partly play, partly testing how objects move, cats are naturally curious about cause and effect.

None of this means anything is wrong with your cat, it's mostly just being a cat.