Given that everyone misses an occasional makeable game it is essential to compensate by making a few unmakeable ones. Prime amongst these are 3NT contracts and William Crook spotted a couple in this years Tollemache. Firstly there was this one managed by Sandy Fulton:

Sandy suppressed his hearts to reach 3NT which received a spade lead ducked to the King. There are seven easy tricks and no time to develop two more if the defence try clubs. Undaunted Sandy played a heart to dummy and lead DQ -covered- followed by another to the J. East now unthinkingly cleared spades and that was nine tricks. East went wrong but the key thing is that declarer helped him err by playing smoothly and by not cashing any hearts; that would give East more time to think and more information about the hand. Note that 4H is hopeless; if you have a choice try a dodgy 3NT ahead of a dodgy 4H.

On the next offering it was William who took advantage of the  opponents: 

William won the diamond lead on table and with no other sure entry took a losing heart finesse. West continued diamonds and William played CQ won by West who played a third diamond. Now the hearts were cashed revealing the bad news when West pitched a diamond and a club to keep his SQ87. That left declarer counting 8 tricks only and wondering how to find an extra spade from AJ6 facing 952. Time to enlist the opponents aid. William cashed clubs and exited with his diamond. East found himself squeezed down to these three cards: SK10 H10,while William kept his spades and West was on lead having to open up the suit. Small to K and A then J pinning the ten created a trick with the nine. Another 3NT made. Obviously with sight of the deal West would retain a winning diamond to avoid the endplay but it is not so easy particularly in a long and tiring event like the Tollemache.