Call me crazy, but I have a theory that you are more likely to find shinies in black than white. I have white and my sister has black. She has found 17 shinies in that game and I haven't any. She will sometimes find two shinies on the same day without looking. I have invested 9 hours into soft resetting for Kyurem and had no luck. She restted twelve times and found one. Coincidence? She has this kind of luck in all of her pokemon games, which are the following: leaf green, sapphire, gold, black.
I know most will think I'm wrong but does anyone else share this THEORY?