Final answer:
People are reluctant to mess up a Rubik's cube when they have one side completed because of the hill climbing heuristic.
Step-by-step explanation:
The reason why people are reluctant to mess up a Rubik's cube when they have one side completed and are stuck is because of the hill climbing heuristic. The hill climbing heuristic is a mental shortcut that focuses on making moves that bring you closer to the goal state. In the case of the Rubik's cube, when one side is completed, it represents a goal state. People are hesitant to make moves that might disrupt the progress they have made, because they believe that they are closer to solving the puzzle when one side is completed.