The Curious Incident Of The Dog In The Night-time; Journal #1

Whenever Christopher sees 4 red cars in a row, it is a Good Day for him, and whenever he sees 4 yellow cars in a row, it is a Black Day for him. I thought this was very unusual, but because he has Asperger's disease, he doesn't think like regular people, like how we think it will be a good day if it's sunny or a bad day if it's raining. Instead, he has a ritual where if he sees 3-5 red cars in a row, it will be a Quite Good Day, a Good Day or even a Super Good Day, but since yellow is one of his two most hated colours, if he sees 4 or more yellow cars in a row it's a Black Day where he doesn't talk to anyone or eat anything or do anything risky, because he thinks something dangerous could happen if he did. Some think that thinking like that is just stupid, but everyone does it in their own way, Christopher just has his own method of doing it.
Christopher likes seeing red cars (which makes it a good day) because red is his favourite colour and he likes things to be in order, so when there is many red cars all in a row at once, he believes good things will happen, and vice versa for the yellow cars. Christopher is a very logical and observant person and that's why he thinks about Good Days and Black Days the way he does.