Suppose you pick up as South:

Q 7 4 Q 8 3 A K J 4 10 7 4

West is the dealer, nobody vulnerable. Christine van der Ven from the Netherlands encountered an uncharacteristic bidding problem.

West North East South Christine Pass 1NT Pass 3NT Dble 4 Pass ??

West's double asks for a spade lead. Christine elected to bid 4 that was passed out. This was the complete deal:

8 6 3 2 A 2 Q 7 A K Q 9 2 A K J 10 5 9 K 6 5 J 10 9 7 4 6 5 3 10 9 8 2 6 5 J 8 3 Q 7 4 Q 8 3 A K J 4 10 7 4

West led two top spades and let her partner ruff a third spade. With the clubs 3-2 the diamond partscore turned out to be a claim. Still, North-South were not happy, since 3NT by South was cold. However, the board turned out to be a 1 IMP gain, since the North-South pair at the other table played in 3 from the North hand. East led her singleton spade, and four rounds of the suit promoted the J, holding declarer to nine tricks. This defence would have defeated a contract of 4 so you see it is better to opt for your 4-2 fit.