Libra - Capricorn

What you like about each other:  Libra friendliness, Cappy reserve. 

What drives you crazy:  Libra talking something to death, Capricorn pessimism.

Both are organized, hard-working and somewhat self-deprecating, making their basic natures meld quite well.  Neither is generally what you'd call a flamboyant type, though of course that's possible with the right Moon and Ascendant signs.  However, if either of these people had those they would probably not be together.  Based on the fundamental nature of their sign, neither is overly impressed with glitz.  However, they are impressed with hard work.  The main conflict this couple may encounter is that both are Cardinal signs and will therefore not necessarily ask before proceeding along the path their believe to be correct.  They don't do this to be impertinent or annoying, they are just self-motivated leaders who set out to do whatever it is needs to be done.  Since it's unlikely that either is on a power trip unless so afflicted by their Moon or Ascendant, chances are this pair will usually be pleased to find out something got done before they realized it needed doing and when they both take care of something redundantly, they'll probably laugh about it.

Since Libra is an Air sign and as such likes to talk, chances are good that communication between these two will be good.  Cappy's practicality will be appreciated and Cappy won't have any problem letting Libra do most the talking.  As a practical Earth sign Cappy will also appreciate Libra's sense of fairness more than many other signs since it allows exploring all angles of an issue, which is usually very beneficial.  Remember that Cappy likes to advance and social climb, so a well-spoken Libra can be a major asset, especially since as a rule Cappies aren't exactly extroverted.

In general, this pair should get along quite well in spite of their signs being square.  Libra could be annoyed by the social climbing or Cappy by the talking, but if other areas of the relationship are sound they should be able to achieve a satisfactory balance.  Neither is inherently emotional and will generally deal with such issues in a logical manner, though neither is known for being able to deal with highly personal emotional conflicts or hurt feelings very effectively.  Libra, wanting fairness, can bend over backwards for peace and Capricorn may not want to argue, especially with an Air sign, meaning their problems may be swept under the rug and not truly resolved.  This is one area they will both have to work on, but shouldn't be an insurmountable obstacle.