Why do i always think like this?

No offense to the first answer, but this is not OCD nor Asperger's. This (to me) just sounds like a personality trait. I am very much like you. I even type IMs and emails in formal language sometimes. Though I am OCD, it is not these traits that defines that. OCD is a completely different diagnosis and disorder. It has nothing to do with formal speaking and thinking patterns. You also seem a little left brain-oriented. Left-brained individuals are more formal, logical, and "academic" than right-brained individuals. Hope this helped.