Way back in November 2015 (yes, this post has been sitting in my drafts folder that long), I posted something in the NaNoWriMo forums about how you can get so close to your characters that it’s almost like having fictional friends.
I know it sounds lame/nerdy/dorky or whatever, but my characters are my friends. Not in the sense that you can talk to them and they talk back, but in the sense that they are parts of you and can help you see different aspects of yourself. Real flesh-and-blood friends help you do this, too, and hopefully the relationship is mutualistic enough that you do this for each other.
Friendship is also about comfort and being able to be your true self around others. You can be yourself around your characters, and you feel comfortable enough hanging out with them even when they sometimes don’t want to go along with your nefarious fictional plots.
Do you see your characters as friends?