I've always said it's a good thing dogs can't buy lottery tickets... all it would take would be a one dollar win ONCE and they'd be playing all the money we gave them for the rest of their life, lol!
While this OCD behavior can certainly be annoying, their rediculous optimism and enthusiasm is also part of the doggie/GSP charm. May as well learn to laugh at it because you'll be hard pressed to erase it (obviously).
We actually were going to rescue until we read that GSPs don't do well with small animals...We had to give up a Weim we rescued for this reason because he tried to eat my Chihuahua. Jackson is great with Sanchez, but he is OBSESSED with squirrels he goes from the back window couch in our sunroom to the front windo chair in our family room and will stalk them all afternoon!! lol! At dusk he can hear the bats that fly around our orange trees.... He goes out just as it gets dark and tries to jump in the air and catch them. It wears him out and which is good for me!! I wonder if he will ever understand that he will not catch one! hehe