It is our choices that show what we are, not our abilities

'Professor,' he started again after a moment, 'the Sorting Hat told me I'd - I'd have done well in Slytherin. Everyone thought I was Slytherin's heir for a while... because I can speak Parseltongue...'
'You can speak Parseltongue, Harry because Lord Voldemort - who is the last remaining descendant of Salazar Slytherine - Can speak Parseltongue. Unless I'm much mistaken, he transferred some of his own powers to you the night he gave you that scar. Not something he intended to do, I'm sure...'
'Voldemort put a bit of himself in me?'
'It certainly seems so. You happen to have many qualities Salazar Slytherin prized in his hand-picked students. His own very rare gift, Parseltongue... resourcefulness... determination... a certain disregard for rules. Yet the Sorting Hat placed you in Gryffindor. You know why that was. Think.'
'It only put me in Gryffindor, because I asked not to go in Slytherin...'
'Exactly, which makes you very different from Tom Riddle. It is our choices, Harry, that show what we truly are, far more than our abilities.'

DOBBY'S REWARD - Pg 352