Well...I've never actually regretted a name I chose, but 3 of my girls were 2 years old when I got them and already had names...they're actually their registered names...and I didn't care for them.
So I changed their names:
From Spiderbabe (Babe) to Brooklyn Babe
From Ella to Mikayla Cinderella
From Dira to Hadley Dira
They've never had any problem changing to their new names...if you say it enough and look right at them when you're saying it...they learn it. They're smart little butts...