I would say this is one of the rare exceptions where you don't have to see the original to enjoy the sequel. The world of the first one is much more populated and to a certain extent less Apocalyptic. But the first film is recapped in the opening 1.37 sequence, but brilliantly. It doesn't feel at all like "Last Week on Mad Max!", instead it feels like you are being fed mythology. If you like The Road Warrior you can then go back and revisit the universe. Its totally up to you. If I would have gotten Mad Max sooner I would have watched and reviewed them in order, only since its been a few years since I watched the original and I tend to watch The Road Warrior once a year.
So there you go!