Everyone's handwriting is unique. An extension of the body used to secretly show the true thoughts of the person writing. Their feelings, their motives, their thoughts; a writer's subconscious may turn words crooked or tidier giving a hint or clue at what lies inside. Just as an artist places a bit of themselves in their work, so to do we as writers. Writing by hand is not just a transference of symbols directly from the mind's thoughts, there's a whole dimension to it regarding the actual craft of placing the graphite on paper.
A person's hand writing is a reflection of their soul.