When loading from a Quick Save, there is an animation of 3 slimes in the bottom right corner of the screen. Most of the time they're plain old blue slimes, but sometimes the middle one will be something else. What is the significance of non-blue slimes here?
First, read this thread about the hoimi table.
WHen you get a Blue Blue Orange Slime loading screen, there are more red (2% rare luck) and blue squares (10% luck) in the hoimi table. Take a look at this picture:
Now, here is a hoimi table for another type of loading screen (Orange-Blue-Blue):
As you can see there are a lot more red and blue squares in the first link than the 2nd pciture.