The Gemara discusses the sugya of Tefos L’shon Rishon, which is a complex analysis of how do we understand the intent and enactment of a statement made, that has two contradictory parts.  The opinion of Tefos L’shon Rishon is that either we assume that his primary intent was in his first words, or that his first words become activated and that whatever is said second does not have power. 

While this may be true in lomdus, in human relations, the usual scenario is Tefos L’shon Acharon.  Meaning, when someone says something such as, “You’re very smart but…”, “You are very pretty but....”, usually the only thing heard is what follows the “but”.  The “but” seems to emotionally disqualify whatever preceded in the statement.  I like to say, “al tikri but, elah batel”.  The “But” is mevatel and nullifies anything prior.

You can try replacing the word “but” with “and”.  It works quite well and conveys an equality to both parts of the statement.  Try it on for size: “You’re very smart…and this comment of yours does not make sense”, “You are very pretty and...I liked yesterday’s dress more.”