Why do some topics have Like buttons under the posts while other topics don't ?

I was thinking of that too! im certainly very confused and have been trying to find out the reason :P

I do not understand the question.

Are you asking why some message board categories are configured differently? Because the trivial answer would be just that. It's different sections of the message boards, and they are configured to have different voting styles.

Is it something we can configure when we create a new topic?