Yes, the frustration is often palpable. That doesn't mean you're wrong. Our own species might be maddening sometimes... ;-)

The "good snob" would be someone who knows his being superior to others, but he strives to channel this feeling into sometimes constructive (like teaching or encouraging others to improve) rather that to just inflate his own ego.

I would consider Oscar Wilde to be a "positive snob": he regarded himself as way above average (and he bloody well deserved it), but usually he depicted others in a benevolent and sweetly ironic manner - not harsh nor cruel.