my ocd latched onto the number 9, i think because i found the property where adding the digits of a multiple of nine will give you a multiple of nine fascinating when i was younger. was kinda disappointed when i spotted that this trait is also exhibited in other bases (eg. 3 exhibits this property in a base 4 system, 4 in base 5, etc.) and it's not unique to 9

so it's debatable sometimes whether i like the number nine or hate it, but it is what it is