Why is it difficult to balance our body when we accidentally step on the peel of banana?

When we walk, a force is exerted upon the surface of the ground by our foot and in reaction, the force of the same magnitude is exerted upon our foot by the ground in a forwarding direction. This reaction force helps us to move forward. But when accidentally we step on the peel of banana, there is no reaction force. So it becomes hard to balance our body.