Stick to Your Reasoning
No matter what, stick to your reasoning and inital decision. If your child asks to go somewhere and you say no - stick with it. If they ask for a popsicle and you reply yes - stick with it. Children need to know that your answer is the final answer. They will respect your decision and know that you will not back down. So instead when you give your child an answer to their question, they will not continue to ask a series of "what ifs."