Exactly What You Wanted

I'm not so good realizing
Who I can or cannot trust
It's best to keep what matters vague
With harmless lies I can adjust
I get a "D" for disappointment
Now there's nothing to regret
Everybody's good for something
At least, you know what you won't get
I let you down again
What's another harmless
Lie between friends?
Now you can be disappointed
I thought I gave you just exactly
What you wanted