post-concert syndrome

The condition developed by some concertgoers after a concert which causes them to feel the urge to buy the entire artist/band's discography and obsess over every detail of their history. This condition typically lasts 1-2 months after the concert, or until the person has acquired everything associated with the band.

Ryan: Hey, what's with Bill?
Dave: He just got back from the Van Halen concert. He's got post-concert syndrome.
Ryan: Oh, that explains having Panama on repeat for the past 6 days.