One of the problems with the luck column is that there is no upward bound on "bad" luck, whereas there is a negative bound of 1% (or 0% if it takes exactly one share to find a block) - you can only have a -99% luck factor, but you can have a theoretically infinite + luck factor. So the color visualization is kind of misleading... if anyone has any ideas on how to improve the luck factor display, I'm all ears.
You could make it so that every +50% or +100% is a new darker shade of red. Then at some point (maybe like +400%) the dark red just turns into a small nuclear explosion.