The reason your fingers wrinkle in the bath is much deeper and more fascinating than you would ever imagine.
According to this video posted by SciShow, the reaction is actually a result of the nervous system's exposure to water over an extended period of time.
Up until 1935, the scientific community attributed wrinkling in water to osmosis, saying the moisture caused dry skin to stretch but not the tissue underneath it.
But, experiments performed by Lewis and Pickering revealed the nervous system is actually responsible for the skin's transformation under excessive moisture.
It appears our brains are programmed to trigger skin wrinkling in such situations because it works to our advantage should we need to grab something wet.
What seems like a natural annoyance is really a useful tool granted by evolution.