This saying actually means the opposite of what you think it does. "Missing the forest" in this context means to ignore it. So the saying is more about not being able to see the big picture because you're too caught up in a single tree.
Hopefully this can help mitigate some of the iritation the saying has for you.
GIRPS is nowhere near as bad as people make it out to be. Most rolls just boil down rolling 3 dice, adding the totals, and comparing them to your skill level.