Union of Opposites - Gryffindor/Slytherin

[houyhnhnm102]

No: HPFGUIDX 156061

Dana:

> Water = emotions and beauty. Symbolized by a cup.
[snip}
> But Slytherin doesn't really seem to fit, do they?

houyhnhnm:

If you want to know what people are really up to, look at their taboos.

Dumbledore, presumably a Gryffindor and probably onetime 
HoH, cautions his young Gryffindor protegee against "that 
flighty temptress, adventure".

What do the last two Slytherin Heads warn about?

Slughorn:  "When you have seen as much of life as I have, 
you will not underestimate the power of obsessive love."

Snape:  "Fools who wear their hearts proudly on their 
sleeves, who cannot control their emotions, who wallow 
in sad memories and allow themselves to be provoked this 
easily--weak people in other words--they stand no chance 
against his powers"

I think this shows that Slytherin is the emotional House. 
I think we see additional proof in Draco with his 
*quivering* smirk (and all the other examples that I 
know have been detailed here before). There are two 
reasons that it is not more evident.  One is that emotional 
natures are under more pressure to learn to control 
their emotions.  The other is that Slytherin House has 
been corrupted by the influence of Voldemort.