I want my child to have a name in the sweet spot. Not too common, not too unique, and, crucially, not a name that is popular for only a brief period so that everyone will know about how old they are just by their given name[0].
But people thinking along these lines inevitably gravitate to the same small handful of names, causing the "too popular for a brief period of time" effect against their will. I've already failed once; my cat is named Olivia, the popular girl's name of the decade, apparently.
[0] My own name is one of those. It's annoying.