What you experienced is a phenomenon known as "automaticity" or "muscle memory." Automaticity is the ability to perform tasks or actions with little conscious effort or attention because they have become highly practiced and ingrained in your muscle memory through repetition.
When you perform an activity repeatedly, such as hand washing dishes, your brain creates strong neural pathways associated with the specific sequence of movements and actions involved in the task. With time and practice, these pathways become more efficient and require less conscious thought to execute.
During your daydream, your brain likely switched to a more automatic mode while still continuing the dishwashing task. This is similar to how you can drive a familiar route while lost in thought and still arrive at your destination safely. Your subconscious mind takes over the well-learned activity, and you can execute the task almost effortlessly.
Hand washing dishes is a repetitive activity, involving actions like scrubbing, rinsing, and placing the dishes in a particular order. Since you've likely performed this task many times before, your brain is capable of handling it even while you're not fully focused on it.
However, it's essential to be cautious with automaticity in some situations. If the task becomes too automatic, you might be more prone to accidents or mistakes, especially if there are unexpected changes or hazards in the environment. So, while it's impressive how our brains can perform routine tasks without conscious attention, it's always a good idea to stay mindful and aware of your surroundings to ensure safety and efficiency.