I had just seen an Alkaline Trio shirt in Hot Topic when I was about 13. I thought the shirt looked cool, so I went home and Kazaa'ed a bunch of their songs. I listened to a song with a pretty guitar intro and fell in love with the opening lyrics "Shaking like a dog shitting razor blades." Later that year, I had my friend show me how to play it.... How could you not love a song that uses that lyric?
The first song that I learned to play was on the bass. It was my girl by the temptations all the way back in 7th grade. My friends and I learned it to impress the girls we had crushes on and then played the song for our middle school talent show. Needless to say it was full of all kinds of awkwardness. My parents video taped our poor rendition I'm sure there's a copy laying around somewhere.