lose sight of the big(ger) picture

To focus on specific details or immediate preoccupations and forget or fail to consider the general, overall, or long-term scope of something. I know it's frustrating scrimping and saving like this, but don't lose sight of the big picture. In a few years' time, we'll finally be able to afford our own house! You're worrying so much about these minor day-to-day challenges that you're losing sight of the bigger picture of our company.