"Have you heard? Your cover band, The Pairs and the Puzzlers, is having a comeback tour without you because you 'always spoil the mood!' They'll be playing these thirteen songs (given in alphabetical order) and if you can find the perfect song to complete their set, maybe they'll let you back in."
21 Guns - Green Day
Ave Maria - Franz Schubert
Bye Bye Bye - *NSYNC
From Nowhere - Dan Croll
Jealous - Nick Jonas
Let It Be - The Beatles
Long Train Runnin' - The Doobie Brothers
The Kill - 30 Seconds to Mars
The Wizard - Black Sabbath
Take on Me - a-ha
Under Pressure - Queen & David Bowie
Wings - Jimmy Buffett
With Or Without You - U2
There is more than one song that could complete this set, so any that work (with correct reasoning) will be accepted. No knowledge of these songs, beyond the information given, is required to solve. EDIT: Knowledge about one song that I forgot about is required; this shouldn't make the puzzle too much more difficult.
"You don't know what to do first? I already gave you four hints!"
"Of course you always spoil the mood! You always speak your mind, saying what you want with no respect for whether or not people want to hear it!"
"There aren't very many pairs that can be formed; if you think you know how to form them, maybe just look up what pairs are possible?"
"Alright, I'll give you a boost. The pair that requires some song knowledge is 'Ave Maria' by Franz Schubert and 'Take on Me' by a-ha."