Preferences —> Memory Usage
Adjustments —> Brightness/Contrast
Filters
Blur (note the rendering of the thumb arrow)
Layer Blending
Layer Style
Threshold
Color Balance 
Things to keep in mind:


[Source] via Daring Fireball
320old, but still incredibly amusing in an alarming way.
Wonderful UI consistency - NOT.
Chances this got fixed in CS5? Oh, wait. They rewrote sections in Adobe Air. None.