Theory on Snape -

[vmonte]

No: HPFGUIDX 109283

vmonte:
"I do however, believe that DD is capable of forgiving people and
giving them another chance (no matter what the crime(s)). Does DD
think that Snape had some kind of epiphany? Like St. Paul, who
realized his evil ways and converted? Sadly, I'm not as forgiving as
DD, and I also find Snape's conversion hard to believe."

DuffyPoo:
But Snape didn't really convert. He was on DD's side all along. He 
went over to LV on DD's orders, and came back after convincing LV 
that it would be a good plan, he could get closer to DD that way, in 
order to spy on him. No conversion necessary.

vivian again:

You mean according to your theory don't you? Per canon, Snape was 
once a DE that switch sides at personal risk. Do you really think 
that DD knowingly allowed Snape to murder and torture people just so 
that he could gain information about Voldemort? This would make DD 
worse than Voldemort IMO.    

vmonte
"The problem with being a great occlumens is that you can fool
everyone and every side. Snape holds some nasty grudges. (Does he
carry a list of people who have done him wrong? Has he crossed off
James and Sirius?)"

DuffyPoo:
You can only fool a Legilimens. No one else can get into his 
mind...that we
know of so far.

vivian again:

I always get these spells mixed up, sorry. 


vmonte:
"Snape isn't just a grouchy guy who snaps at children. He's pretty
nasty! Granted, it could very well be that long term association
with Voldemort turns people crazy. Or that there are certain spells
and magic that corrupt the soul, turning their victims into dark arts
addicts. I think that DD keeps Snape from becoming the DADA teacher
because it will fuel Snape's addiction. There is nothing nastier or
sader than an unrepentant drug addict in denial."

DuffyPoo:
Nastiness is a good cover, isn't it? Can't let the little kiddies - 
or anyone else - figure out he's really a good guy. Might get back to 
the DEs, especially now he's got Malfoy, Jr., Crabbe, Jr., Goyle, 
Jr., and Nott, Jr. all in his Potions classes.

vivian again:

Didn't JKR say something about Snape's personality? Something about 
children aren't fooled by this kind of teacher (I know I'm 
misquoting). I really think that with Snape what you see is what you 
get. Adults have a tendency to rationalize behavior in a way that a 
child does not. I think Dumbledore is in for a nasty surprise.

vivian