At the ages we support we have seen children trying every manner of ploy to get their way. Pouting, tantrums, arm crossing, yelling, and many of the granddaddy of them all - "NO!". And this is expected. Just as an infant cries to fulfill needs it doesn't understand, younger children try a variety of things in an attempt to get what they want or need. This isn't "mean" manipulation any more than an infant crying would be considered so. These behaviors are simply an expression of the limited experience and tools that a young child possesses.