Children are nasty. This is not a hypothesis. It was until I put the steps of the scientific method to use and observed the test results.
Step 1: Consider the problem. I consistently have a sink full of dirty dishes and an empty dishwasher. Hmmm. It seems I am solely responsible for putting those dishes in the dishwasher even if I did not dirty the dishes.
Step 2: Formulate a hypothesis. Children are not self sufficient; they are in fact filth mongers.
Step 3: Create a prediction. The children will not put any of their dirty dishes, water bottles, pots and pans they played with on the floor in the empty dishwasher. It will be left for me.
Step 4: Test the hypothesis. I will leave the dishwasher empty and see if the children make use of it.