Go with the flow

Got into a discussion with a colleague who was talking about a book he's reading - Flow. From what he summarized, the book talks about why one should be living in the moment and not worry about anything else.
Mihaly Csikszentmihalyi (Author) is honest about the fact that this concept has been much written about.
I agree.
So the challenge is not understanding why one should be in the moment and not worry about anything - it's the how ? which is hard to find an answer for.
I believe that we apply Newton's third law of motion in everything we do - we expect a reaction (a positive one at that).
Now if we stop doing that and this is not new - Lord Krishna said this
in 1000 / 1400 B.C.s
Everything seems simple.
Like Nike has been saying for years .. "Just do it" ! :-)