I love surfing!  The ocean is awesome.
I have never done it.  I see that it is surface water sport in which the surfer rides on the deep face of a moving wave
yes.  It is very challenging - body boarding is definitely easier
apparently you can surf in either the ocean or even lakes or rivers in the form of a standing wave or tidal bore
i did not know you could surf in lakes!
You can also surf with artificial waves such as those from boat wakes and the waves created in artificial wave pools