Because you need to eat it, like, now
Damn, an avocado with salt is awesome. Too bad the one you were hoping to eat is still totally under-ripe. Here, a speedy trick to help it ripen faster (AKA almost overnight).
What you need: An apple, a brown paper bag and that not-quite-ready avocado
What you do: Place the apple and the avocado together in the bag, then fold over the opening as best you can to seal it off. Let the fruits sit together overnight and--voilà! You'll have a ripe avocado, ready to be enjoyed.
Why this works: Apples give off ethylene, a naturally occurring gas required for the ripening process.
So does this work with other fruits and veggies? Yup! Bananas, corn, tomatoes...sometimes nature just needs a little help.