some of it makes no sense - Ravens on your house give you dark magic? Becoming a gymnast makes you stupider?
It does make some sense. The ravens are of course one of the more obscure examples, as the association of "raven"="bad/death/etc." is completely arbitrary. Some cultures might very well associate ravens with the opposite concepts, or nothing at all. Still, in a magical world it
could be that ravens tend to be attracted to births of dark mages.
However, the hobby you indulge in certainly affects how you develop as a whole, so it can be said that if you focus on gymnastics, you neglect furthering your intellect and thus remain (not become) "dumber", just like the math puzzle enthusiast will neglect their physical development. Obviously there can be exceptions, but those are not commonplace.
Anyway, we all know that the CC is there in order to hide numbers. It can also serve as inspiration, and to get a general idea of the mood of PS. Also, it may be completely ignored if you have a different background in mind (as long as that ties in neatly with the settings, that is).
Besides, it would be weird with practically every person saying they were 'cook's assistants' and 'fell in love with a thief' and got beaten a lot.
Seeing the amount of duelling ingame, the last part certainly seems realistic. What I find most amusing about the CC, though, is the idea of a significant number of people being born during a crystal eclipse.
Edit: If you are actually asking for what to select in order to maximise skill X or stat Y, then I don't know. I didn't memorise the effects of the selections, and they may very well have changed since I made my char. It usually boils down to a few hours of experimentation, as has been stated.
Also, whatever you end up selecting, you should remove it from the description in any case, since none of that can be known by looking at your character. Replace it by a general description of your character, which doesn't need to be detailed or long.
