Not the contradiction between the forces and relations of production? No, not that one. This one, as sung about by Lyle Lovett:
And it's the classic contradiction
The unavoidable affliction
Well, it don't take much to predict, son
The way it always goes
One day she'll say she loves you
And the next she'll be tired of you
And push'll always come to shove you
On that midnight rodeo
Or you might prefer it in this manifestation:
If they want to come and play in my yard, they can.
