When you start a Guitar Hero or Rock Band session and continually tell yourself or your friends that you'll do one more song and then it's over.

The next time you look at the clock, three hours have passed and you've played nearly every song on the disc.
Person 1: I can't believe we played every downloadable Foo Fighters song Rock Band has to offer! What do you want to do next?
Person 2: How about one more song?

Two hours later:
Person 1: Alright. We've also played every Blink-182 song there is. Think we should go to bed?
Person 2: I've wanted to play 'Rebel Yell' for the last twenty minutes.
Person 1: Rock on!

One hour later:
Person 1: I think we've got the syndrome.
Person 2: What syndrome?
Person 1: One More Song Syndrome.
Person 2: No wonder we're virgins
by EderC October 13, 2010
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