There's no bottom to deep water. Nothing you can stand on. Nothing you can touch. It is emptiness, except for things that might eat you, things that live in the deep water. Things you can't see from the surface. You are small, and deep water is the Abyss. The thing that Nietzche was afraid to look into.
The depths are transformative. Whatever you were on land or in the shallow water, you had something solid to touch. That lack of something to touch defines deep. At the very least, you must be in over your head. It is transformative, it must be, both because you need to learn to live, see, think and breath without your reliable constants...and because it is a world in which your reliable constants have never even existed. That which feels eternal, never existed at all. Not here. Not in the deep water.
No matter how closely you watch the shallows, no matter how many years you spend wading at the shore, no amount of concentration will turn shallow water to deep. Depth is a thing that is there. You must go to it. You can not create the abyss in a safe place. If you have touched the abyss and not been changed, it wasn't the abyss.
There's lots of deep water out there. Mine. Yours, maybe.
The T-shirt from Robb is one of Joe's favorite sayings: "Follow Me To The Deep Water."
It's over here, but you have to let go of the bank.