My favorite is https://news.ycombinator.com/item?id=5728843 https://news.ycombinator.com/item?id=5728843 and https://news.ycombinator.com/item?id=5728844 https:

My favorite is https://news.ycombinator.com/item?id=5728843 https://news.ycombinator.com/item?id=5728843 and https://news.ycombinator.com/item?id=5728844 https://news.ycombinator.com/item?id=5728844, where two people post the exact same article within presumably minutes of each other, and manage to achieve sequential ids.