From the day kids are born, they are motivated by what they want and don't want. They start out crying to get their way, because that is the singularly most effective way of accomplishing it at that time. People do not like to hear a crying baby for very long. It makes grown-ups sad, grates their nerves, and generally spurs them into action to solve whatever problem needs attention.
When they are able to talk, children start to ask for what they want, and protest what they don't want, typically, with the word NO! For example, the parent says, "It's time for bed.". "NO!", says the child who is resisting an end to play and fun, and exciting things. There is only one inflection in which this word is delivered, and it is always ALL CAPS with an EXCLAMATION POINT. This is the stage where parents begin to become truly annoyed with resistance, but are usually able to re-direct the child by making a game out of the offending task.
Then comes the stage I am currently experiencing as a parent...Continuous and Constant Negotiation, or, the Struggle for Ultimate Power. This is the most challenging stage of resistance, because meeting the need, or offering distractions no longer do the trick. This is the stage of life when teachers start to remark that you may have a great future as a lawyer for the ACLU. I know this, because a teacher once said that exact phrase to me. I could reason and argue more effectively, and for longer periods of time, than anyone. That was before I met my daughter. :0/ That girl has a great future...with the ACLU. :0)