I mean, little things that will always get you in a song. I can't explain this very well so I'll do a list and hopefully you might get what I mean.

Beautiful feedback or static - perfect example - Yo La Tengo's Damage. Just little waves of it that somehow envelop you and are just hypnotic and wonderful. Also the end of Ashes Of American Flags and Poor Places by Wilco, how can radio noise sound so amazing?

Pedal steel guitar - I really love when you get that warm, twangy sound at a moment you're not quite expecting it.

A well placed catharsis - just when a singer emphasises his emotion by suddenly screaming/yelling/sounding as if they are about to cry. "AND THE BLUES, I GOT THE BLUES, THAT'S ME!!"

Buzzsaw guitars - just the summery pop punk stuff that makes me feel really really happy. Case in point - Ash's Burn Baby Burn.

Tension and atmosphere - when an album builds up a sense of anticipation or foreboding to a point where you know something's going to break. This is hard to define but I think you'll know what I'm getting at.

Add your own. I really hope this isn't a shit thread :S