This really seems to happen to me, and it's so frustrating.

It is the same feeling as not being able to remember "that actor's name".

But in this case, it's a "cool idea" I had while zoning out, and when I kind of "come to" and robotically start doing whatever with my hands and jump to the next thing or task, whatever he thing or whatever the circumstances.

It's then that I remember that I must remember. Those two 'remembers' must cancel each other out, because this situation is sometimes remember poison for me. The harder I reach, the more the the squirrel runs away into the underbrush.

It's odd that dreams can be like that. Reaching, retreating, reaching, more disappearing into vapor. "Bye-ee!"

I wonder if the "trick" is to be very still (mentally). Probably so, if the analogy holds. But then again, that squirrel is gone and never really needed you in the first place.

[See also: Pratchet, Particles of raw inspiration.]