“Oh thank heaven for 7-11.”
7 is everyone's lucky number. It's especially lucky for people who are using loaded dice. Diced carrots, even better.
Seven was invented when mathematicians were looking for something to follow 6. Luckily (see!), 7 turned up at just the right moment. The 7-tailed fox is particularly auspicious in Japanese folklore since nobody can sneak up behind it and blow smoke up its asshole. They also regard a house with 7 roofs as being lucky, as you will never see roofers ever again and a confused Santa will go down multiple chimneys and leave too many presents.
And the Seven Deadly Sins: how lucky is it if you can commit all 7? It worked for Snow White, after all.