Omg, for reason this week everyone is asking me that XD
Please understand their songs aren't actually depressing like Simple Plan's are. They are a different type o_O
OH! I KNOW WHY XD The lyrics in that song right? Well here I'll post the whole song and you'll see why it's depressing:
Summer has come and passed,
The innocent can never last.
Wake me up when september ends.
Like my fathers come to pass,
Seven years has gone so fast.
Wake me up when september ends.
Here comes the rain again,
Falling from the stars.
Drenched in my pain again,
Becoming who we are.
As my memory rests,
But never forgets what I lost.
Wake me up when september ends.
Ring out the bells again,
Like we did when spring began.
Wake me up when september ends.
^ That's part of it...the song is about Billie's dad dying (His dad died out Esophagus Cancer when Billie was 10) But for some reason they made the music video about 2 people loving each other XD