Текст песни Stupid Is As Stupid Does

Stupid is as stupid does
That's what mother said
Stupid is as stupid does
But no one cares
Stupid is as stupid does
What do you mean?
Are you trying to say that I'm stupid?

Stupid is as stupid does
That's what they all say
Stupid is as stupid does
But we don't careAbbreviated. Life. Expectancy. - Stupid Is As Stupid Does - http://ru.motolyrics.com/abbreviated-life-expectancy/stupid-is-as-stupid-does-lyrics.html
Stupid is as stupid does
What does this mean?
Are they trying to say that we're stupid?

Stupid is as stupid does
And you are
Stupid is as stupid does
Yes, you are
Stupid is as stupid does
You're a fool
Yes, I said that you're stupid