Now I wonder what happens with the thread "Like" how do I see the result of that?
The Like/Share buttons above the Quick Reply box are Facebook buttons; these are not involved at all in the calculation of the likes feature, which is a compilation of data in your ubbt_likes table.
You can "like" your own thread as it is attributing an activity to your Facebook account; whereas an admin must allow users to like their own content as it'll provide local statistics for liked content (and users liking their own content could skew any stats).