Horcrux question

[spa76]

No: HPFGUIDX 187795

Sandie: Once again I have a burning question I'm too embarrassed to ask my real-life HP-fan friends about... 

It's established in HBP and DH that a horcrux is incredibly difficult to destroy, and that each contains a bit of Tom Riddle's soul. So why is Hermione apparently unaffected? I know the Ron and Hermione Chamber of Secrets trip is one of the series' big "missing moments," but when they're retelling the story, it seems like it was incredibly easy for Hermione to destroy Hufflepuff's Cup. That has never made much sense to me, considering how much the locket tormented poor Ron before he could destroy it. 

Are we supposed to think Hermione was so focused she just stabbed it with a basilisk fang straightaway, before Riddle's soul could play any mindtricks on her?