Usually when I'm daydreaming, I make up characters on the spot, but let's be real, they're still me under the hood. How convenient that this badass rogue woman and this undead man and this magical girl all have more dramatic versions of my baggage.
Occasionally I imagine my ideal self and they're taller and have a more masculine jaw. I can't really achieve that in real life so I try not to dwell on it too much. They're also a lot calmer and more in tune with people around them though, and I think that's an image worth keeping in my head.