Drawing from the draw or discard pile requires players to carefully weigh their options in light of their current hand and the possible strategies of their opponents. A card that does not add to your current sets or rrummy nabob 777 downloaduns, for example, but might help an opponent finish their hand, might be better to discard right away rather than keep. Also, letting go of cards that aren't useful is only one aspect of strategic discarding; another is deciding what to keep based on what you see other players doing. An opponent may be attempting to form particular combinations if they have been routinely selecting particular ranks or suits from the discard pile.