The answer to 'why is my patio mud' is that your patio is likely experiencing poor drainage, leading to a muddy surface. This can be caused by a variety of factors, such as heavy rainfall, a high water table, or soil with a high clay content that doesn't allow water to percolate properly.
Some common symptoms of a muddy patio include standing water, sinking or uneven pavers, and a slippery, soft surface. To address this issue, you may need to improve the drainage system, add a gravel base, or consider replacing the patio material with a more permeable option.