《Bad Day》是鼠來寶（原聲帶）的歌曲，歌詞為：
It's a bad day
I feel like garbage in the bin
In the bed, feeling dead
Feels like a million bricks on my head
Got my brain in the sand dunes
But I know that I'll come back again
Yeah, it's a bad day for me
It's a bad day for me
It's a bad day
Bad day, yeah
Bad day, yeah
Bad day, yeah
Bad day, yeah
I'm feeling like a broken vase
I'm falling down, I'm shattered all over the place
It's a bad day, yeah yeah yeah
So many problems to face
I feel like I'm living in a box
Got no joy, got no fun
Feels like my life's a load of grueling stuff
Got my heart in the pound office
But I know that I'll come back again (Yeah)
It's a bad day for me (bad day)
It's a bad day for me (bad day)
It's a bad day (bad day) yeah (bad day)
Bad day, yeah (bad day) bad day (bad day) yeah (bad day)
It's a bad day for me (bad day) for me (bad day) yeah (bad day)
Yeah, it's a bad day for me (bad day) for me (bad day) yeah (bad day)
Bad days, yeah bad days, yeah (x2)