I new to the road cycling world and was wondering what exactly makes a good frame good.

I'm not talking about the obvious stuff - cf vs. aluminum vs. steel (material differences)

Many of you experienced bikers can just see two frames and instantly compare them - what are you looking for?

Is the aerodynamics?
Welds?
Symmetry?
Weight?
Manufacturer?
Warranty?
Finish?

It's just that many people frown on certain bike frames (cheap ones, no brands, etc...) but to me they are exactly the same as more costly ones and perform the same duty (holding everything together).

I can see why which components (gears, shifters, rims, wheels...) are prefered since the better ones are lighter, more precise, have less failures (less shifting problems) and are more effecient.

The trouble I am having is just seeing what is so important about the frame (and I know that it is vital). I see two Aluminum frames with similar weight and specs but yet one is bad and the other is good - the only major difference is the price... To me a frame is just to hold everything together, it doesn't move (unlike the components) - it just sits there, so if two frames are made out of Al 6061, why are some so much better than the others?

Thanks for putting up with my newb questions,