A past girlfriend and I would occasionally (cheerfully) quibble over the optimal strategy for extracting toothpaste. It occurred to me recently that the disagreement was fundamentally about amortized vs. worst case complexity. Being lazy, I tend to squeeze the toothpaste out of the front of the tube, optimizing the time spent in the moment and reducing the degree of control required since pressure is exerted near the toothbrush. She would carefully squeeze the tube from the back, maintaining a flat region that would slowly grow as the toothpaste emptied.