At airport, I changed a few times of the lines to drop off bags, somehow, right after I changed, the line opened up and the person before me had something to delay the progress. I’d be much better off just stay at 1st line. I reminded myself the Chinese old proverb ‘ ‘ (rush result in the opposite). Later at security, I saw the other line moving, switched, then watched the person behind me who stayed went way before (20+) me. You could attribute to luck yet it’s better to learn a lesson and move on.