Characters
I was born with big gums, sir.
— Bubba · Forrest Gump

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
Offered politely with a 'sir', this is a plain, guileless explanation of a physical trait, as though the feature were simply an inherited fact requiring no apology. The earnest delivery makes an unusual detail sound like a reasonable answer, giving the line its comic innocence.
Context reviewed