He's so dark...

I heard this phrase (with the ending) a lot about 6 years ago, but I can’t remember how the rest of it went.
It referered to someone’s outlook on things, along the lines of ‘My future’s so bright…I gotta wear shades’.
Anyone know the rest of this?

“I study nuclear science,
I love my classes,
I got a crazy teacher who wears dark glasses,
Things are going great,
and they’re only getting better.
I’m doin’ all right,
Getting good grades,
The future’s so bright,
I gotta wear shades.”

Song by Timbuk 3. I think it was the theme song for the TV show Head of the Class. A Google search should turn up full lyrics.