What's so wrong about making up a new name for a baby, or choosing one that is uncommon?

[Turquoise]

I think that this would make sense if people were at all reasonable but they're unfortunately not. They'd go for some incredibly wacky name like the example you used - Hashtag. That's why originality is shunned - because people can't seem to wrap their heads around what is unusual and acceptable versus what is unusual and utterly ridiculous by others' standards. I think making up names is a wonderful route to go but only if you've considered what could go wrong with that name - perhaps spelling or pronunciation or god knows what else. As long as you are confident in your own decision, the name will be fine. The "common" names of today are those that have survived the trials that time presents and the ridicule that surely accompanied them at their beginnings. Those are the reasons that classic names are beautiful too, in their own way.