What do you think Shakespeare's personality was like?
I know there's very few (if any) accounts of Shakespeare's personal life, and this is often used to discourage discussion on the topic, labeling anything someone could say as educated speculation at best.
But doesn't the lack of letters and other windows into Shakespeare's personal life tell us something in itself?
Shakespeare was born in Stratford-upon-Avon, a town about 100 miles away from London. That's where he was educated, where he met his wife.
We can assume that Shakespeare had little assistance in beginning his career as a playwright (his father was a glovemaker). So he made this 100 mile journey in 1580s England, largely on his own. We also know that his wife didn't come with him. She stayed back in Statford, raising his kids.
From this, at the very least, we can say that Shakespeare was insanely ambitious, willing to be completely separate from his family for much of the year. He put his art above all.
In order not only to function but to succeed in such a set of circumstances, we can assume that Shakespeare was rather comfortable with being alone, self-driven, and confident in his own decisions (imagine what a small town in 1500s England would of thought of a young guy running off to London to be a playwright).
Shakespeare was almost certainly introverted, yet capable of being bold and assertive (those plays got on stage somehow). He would've had to have been fiercely independent, building his own reputation in the London Theater Scene, willing to isolate himself from everyone in Stratford (which is very possibly everyone he knew).
The reason that none of his letters survive is because he probably didn't write very many: personal relationships took a backseat to writing; he likely had very few close friends, being so obsessed with his work. Furthermore, His capacity for empathy requires a deep understanding of others, and it's not too far of a reach to say that he distanced himself from other people because he knew what they were capable of (think Iago, Regan, and Goneril).
Shakespeare was a loner genius who knew exactly what he was capable of. He was the ultimate "Fuck you, watch me" artist.