Toddlers are very adventurous and often fearless. They are entering a stage where they are very curious (Piaget called children at this stage of development "Little Scientists").
The Toddler is all about cause and effect and making things happen (i.e. "what will happen if I push this, pull this, etc...") They enjoy exploring objects to see what they will do and some of these things are not so fun for the grown-ups in their lives. Basically, it's the food-throwing, cup-spilling, shoe-removing, cell phone-stealing phase.
Toddlers are also entering the era of the "boo boo" as they are not as steady as they are curious and fearless. Their sense of body control and space is just beginning to emerge. This is all part of the process of developing body mastery. In other words, learning how to walk, run, jump, go over, go under, get in and get out. Very often, Toddlers will bump their little bodies and heads around during their activities and body mastery practice. Of course we work hard to create a safe play environment and space with plenty of supervision, but even then and at home too, you will undoubtedly be in for some of life's first boo boos as your Toddler learns how to move around their world.