Bad Moon Rising. Played the wrong way in standard tuning, D, A, and G. I told a friend, Teach me that, and that's it, that's all I ever want to know! 38 years later and I've learned thousands and still learning!
I bought the guitar the day before I learnd it and remember deciding (I'm left handed) if I should use it the "Hendrix"-way or just learn how to play it as it was intended. I did choose the latter and I can see now how that decision made my life easier.