Paying attention to what your opponents are collecting is crucial because it's dangerous to discard a card that might aid them in finishing their melds. Finding the 666 rummy 51 bonusThreats and Opportunities. A player may be nearing the completion of a meld involving those cards if you observe that they are regularly taking cards from the discard pile. In these situations, it could be prudent to keep any cards that might help them while looking for other options for your own melds. Giving Up Unwanted Cards.