The feeling you get the day after you see a really fantastic gig. You get depressed that it ended, and want to go back in time and relive the moment, even though you know you can't. Can last up to a week, depending on the awesomeness of the gig.

When you eat dirt for the first time and leave your family to build a shack in the woods

The soul crushing feeling you get after a gig. You feel your heart aches for the band you have seen live and the emotional pain that comes with listening to the bands music makes you want to break down and cry. Huge desire to relive the concert. Stops you concentrating and you suddenly realise you're thinking of the gig all the time. No event in life can live up to the concert. Can last up to 2 weeks or even more. Relapses frequent. Jealousy of others having better gig experiences than you.