Quite a lot actually as I’m sure most creative fiction writers would agree. I invest a lot of time and effort in choosing the right name for my characters. It's a huge part of making them live.
For example one of the characters in Driftwood started out as a bit-player – there to play a small role in one of the sub-plots. But as I continued with the story so he began to get in on more of the action, eventually becoming a possible love interest for Juliet. As a bit-player I hadn't spent much time thinking about his name, and as he was Australian I called him Bruce. Sorry if you don’t consider it an Australian name, and apologies to anyone called Bruce for what I’m about to say!
As Bruce began taking on a larger role I started having difficulties with the writing. Reason being I just couldn’t consider a character called Bruce as a romantic proposition (I’ve already apologised!) So he had to have a change of name and became Alex, and yes there are probably people out there going ‘oh no, not Alex, that’s not romantic.’
Which I guess leads to the question. Have you read a book where the name of the main character really put you off? Or a name seemed to be a bad fit for a character?