you can't be half pregnant

From the notion that someone is either pregnant or not.

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you can't be half pregnant

1. (idiomatic) Said of an either-or situation; there are only two available choices.
   • 2011, John Warrillow, Built to Sell: Creating a Business That Can Thrive Without You, Penguin, →ISBN, page 47:

     Alex, you can't be half pregnant. If you keep doing other work that falls outside of your logo design process, you'll send mixed messages to all of your stakeholders.