Of course, it is.
Because the action is always different than the planning.
I stumbled across this quote while reading about the writing life from Steven Pressfield.
In it, Pressfield goes into detail about the differences in professional writers and amateur writers.
All of it made me think of this post by Jeff Goins.
“It is one thing to study war and another to live the warrior’s life. —Telamon of Arcadia, mercenary of the fifth century B.C.“