“Add Gatorade to my Groceries list”
and Siri does the rest.
Of course you have to actually have a Groceries list (which you make in Reminders by tapping “Create New List…”). It works with other things too, not just Groceries, and not just Gatorade. I want to make that clear. Just remember to start your request with the word “Add.”
Anyhow, if you go into Reminders, make a few lists, and then let Siri do the rest you are going to be one organized person.
Most people write stuff down so they don’t forget things. Totally wrong. The point of writing stuff down is to ALLOW you to forget, because knowing that these little things are written down somewhere means you can stop clogging up your mind trying to remember them, and therefore have brain capacity for doing other, bigger, things.
Naturally if you’re an iCloud member, and you have an iPad, or a Mac with Mountain Lion (10.8), the reminders you make on your iPhone will show up on your iPad and/or Mac. That’s pretty cool too.