A storage bag shifts between a flat configuration with first and second sidewalls positioned adjacent to each other, and a stand-up configuration with the sidewalls separated. In the stand-up configuration, the bag has a substantially flat base (i) formed by the bottom portion of the first and second sidewalls, and (ii) outlined by at least one of the shift regions of the sidewalls. An angle α is defined between each of (i) the first shift region of the first sidewall and an adjacent edge of the bag and (ii) the first shift region of the second sidewall and an adjacent edge of the bag, and (b) a differing angle β is defined between each of (i) the second shift region of the first sidewall and a bottom edge of the bag and (ii) the second shift region of the second sidewall and the bottom edge of the bag.