Too many to mention. I would never give them a name that is really old fashioned for the time like Gladys or Milton. Those names are fine, I'm sure but not in this day and age.
I would never give them a name that people would make fun of either. When I was a teen I loved the name Dagmar. Really wanted to have a daughter one day and name her Dagmar. Then realized kids being kids that they would like end up calling her "dog barf" so luckily for my daughters, I changed my mind when I matured enough to have children.