Most of the time, bidding is rather straight-forward, but then when the opponents get into the act your difficulties can increase geometrically, especially at match-point duplicate.  Here is a delightful two-suited hand, non vulnerable:
 
SOUTH
ª A
© A J 10 8 7 4 3 
¨
§ K J 7 5 2

 

Partner opens 1 diamond. Ah, the sky’s the limit - if you can find a fit!  Before you can answer 1 heart, East interferes with a 1 spade call.  Now what?  The bidding so far:

 

WEST       NORTH       EAST       SOUTH
                  1 ¨            1 ª            ??

 

The natural option is to bid 2 hearts.  There is some risk of a misfit, and a good chance you will never find a club fit if there is one.  Also this is not forcing; even so, partner will not likely pass with some heart support.  Alternatively you could double to show both clubs and hearts, but this suppresses a very good heart suit.  So you decide to call 2 hearts.  Partner jumps to 4 hearts and East persists to 4 spades.  What now?

 

WEST       NORTH       EAST       SOUTH
                  1 ¨            1 ª           2 ©
  Pass         4 ©            4 ª           ??

 

What have you promised partner?  Certainly you promised a good five-card heart suit, and at least 7 points.  Thus she should have a hand worth 18 points or so in hearts to jump to game.  It’s decision time!  Double for penalty - no, you are too good offensively and too few tricks on defense.  If you are thinking of calling five hearts, I can tell you that many opponents will push to five spades and you have about the same problem again.  Of course you realize that if partner is short in clubs or has either the queen or ace slam is a good bet -  and so you contract for six hearts.

 

This deal was played at a tournament in Toronto.  Six hearts made easily for a tie for top and 8.5 match points (partner had a singleton club).  The next best result was five spades doubled by East.  This was set three tricks, giving N-S 500 points but only 3 match points.