Is this an understandable thing or a bad thing?

I had lunch with my girlfriends yesterday and one of them said she tried to read my novel, but she had to keep putting it down because all she could hear was my voice reading it to her.

While I can understand this, it makes me wonder if this is a flaw with my storytelling or if it is only natural to ‘hear’ your friend’s voice when you read something they’ve written, whether it be a letter, a sticky note, an e-mail or a novel.

What do you think? Is it something to be concerned with? I mean, I do want my friends to read my novel, but if they can’t get past ‘my’ voice, how are they going to hear my characters’ voices?