I used to sew bag linings the same way every single time. Same seam allowance as the exterior, same steps, same little moment of optimism like maybe this one will be different. It never was. The lining always puffed up. Sagged. Looked like it had no idea where it was supposed to live inside the bag. And of course I blamed everything else — my pressing, my fabric choice, my machine. Because clearly it couldn’t be the way I was sewing it… right? Except it was. What finally fixed it was such a smal