We all have something to say, and how we say it is unique to us. No one else can say what we want to say in quite the same way. Let’s say for example there are two different people writing on the same exact topic, and they don’t put their names on their paper. They give them to you (you’re blind folded when they give them to you so you don’t know who gave you what), and you read them. Will you be able to tell which paper came from which individual? One’s personality comes through in their writing. If you don’t know the writer personality, would you still be able to tell? Whether or not we know someone doesn’t take away from the fact that their writing is still unique to them.
This uniqueness is your voice, your light. Who you are comes through on the pages. Whether you’re writing in one character or in more than one, your words are the words that are bringing the story to life. Don’t hold back for fear someone might not like it, because, truth be told, there’s always someone out there who won’t. That’s part of life. Put your all into your work. Put your light into it and let it shine.
As a side note here, if you are editing someone else’s work, be careful to not change too much because you run the risk of inserting your unique style into their work, then it won’t be theirs. You don’t want to take away from their voice/style. A better idea would be to suggest the type of change that’s needed, and let them to the changing.