What is the origin of the idiom "the deep end" and when to use it?

The idiom "the deep end" has its origins in the world of swimming pools. It refers to the part of a pool that is furthest from the shallow or safe area, where the water is typically deeper and more challenging to navigate. The deep end is associated with greater risks and difficulties due to its depth. This expression is used to describe a situation or experience that is intense, challenging, or overwhelming.