When you put your iPod on shuffle at party or social gathering and you project yourself forward thinking "What's it going to play next?" Jarvis Cocker is often credited as coining this term.
Guy 1: "Dude this is awesome. Those songs transitioned into each other perfectly. I wonder what it's gonna play next"
Guy 2: "Oh no, what is it gonna play next?! Will it be as good?!?"
Guy 1: "Dude you're getting Shuffle Anxiety"
When one sings karaoke and acts like the person who sings the original version of the song
Guy 1: "Dude, you wanna do karaoke tonight?"
Guy 2: "Sure. But not if you're gonna sing 'I Can't Get No Satisfaction' and dance around or sing 'Wonderwall' while leaning into the mic with your hands behind your back! I hate Method Karaokeing!"
Guy 1: "How about I sing 'Won't Get Fooled Again' and I swing the mic lead around?"