Aunt Polly can be a big old pain in Tom's neck. She scolds Tom. Sometimes she even hits him with her thimble (a punishment that seems extremely humane when compared to the schoolmaster's wicked beatings). But who can blame her? Tom does get into a lot of trouble. He skips school constantly. He goes missing for days, is presumed dead, and then reappears, happy as a clam, at his own funeral. Ask yourself: do you think your mom would act so chill?
Truth is, Aunt Polly's pretty cool, considering what Tom puts her through. She can be a bit foolish sometimes, what with her miracle cures, superstitions, and feeble attempts to ensnare Tom, but her foibles are endearing. And she demonstrates her love for Tom so many times that you can't help but love her too.