The human body is limited in its ability to withstand the pressure of the water at depth. As a person dives deeper, the water pressure increases, and eventually becomes too much for the human body to handle. This can cause serious health problems, such as decompression sickness, which can be fatal. In addition, many people find it difficult to see and breathe at depth, which can make diving a dangerous activity. For these reasons, it is important to stay within the limits of your ability, and never dive deeper than you are comfortable with.