I never used to win the game try and pull the checkout girl while buying five identical items of opponents choosing.
Always a no score draw in every sense of the word. Me and my pal shit at chatting birds up, but great at picking difficult items.
A variant is to find very unlikely items and slip them into the baskets of people very unlikely to buy them. Multipliers for item-type and vicim type, 4 x bonus multiplier if victim too embarassed to kick up fuss and reject them at checkout, 15 x bonus if victim gets ticking off from partner at checkout, etc.