With the added benefit of promoting mental dexterity and strategic thinking, playing 777 Rummy with friends and family fosters friendly competition and social interactionrummy joy 51 bonus list. It's a fun card game that can be played for hours & is a great way to spend quality time with loved ones. There are several advantages to playing 777 Rummy for social interaction and mental stimulation. To form sets & runs that add up to seven or multiples of seven, players must use strategic thinking, memory, and fast decision-making.