Source of LV's evil nature

[gelite67]

No: HPFGUIDX 113340

I keep wondering why LV is so evil.  I mean, OK, his Muggle dad 
rejected his mother because she was a witch, but is that really a 
sufficient reason to totally go off the deep end and want to wipe out 
everyone who is not pure blood (which, ironically, would include LV 
himself)?

I've thought about DD's comment to Harry in SS that men have wasted 
away in front of the Mirror of Erised, and have even gone mad.  Is is 
possible that Tom Riddle discovered the mirror and saw his family, 
the way that Harry did?  Only it wasn't a source of comfort to 
Riddle -- it made him bitter because he didn't want that to be the 
desire of his heart?  And that he visited the mirror so often that 
his bitterness turned to insanity?

This smacks of something else DD told Harry, about our choices rather 
than our abilities determining who we are.  Harry choose to see his 
family in the mirror as a good thing.  Harry could have deeply 
resented the fact that he had to see his family in the mirror (as 
opposed to really having them in his life), but he didn't; perhaps 
Riddle took the other route, again emphasizing the 
similarities/differences between the two.

Angie, going off the deep end again.  
(Anyone care to join me?  The water's fine!)