The essential fact to remember about children is - they are as naughty as they are allowed to be. All children like to find out where the lines are, and the best way to find if a line is there, is to cross it now and again. The method of crossing, and the distance crossed, depends on the child and the parent. I always used the same approach with my three girls - be nice, I'll be nice, be nasty, I might be nastier! It did work, although they are all different, and required varying degrees of discipline from almost none at all - raised eyebrows being enough, to some pretty heavy tactics, grounding etc, but they've all turned out OK in the end. Remember, our children don't 'belong' to us, they're just lent to us for a short time, so make the most of it!