We have a tendency to look at our present moment and the actions we take in that moment as a kind of direct cause and effect relationship. Do something and get a result.
Using a different perspective we could say that our action in the present moment is like tossing a pebble into water. The pebble causes ripples to spread out from the point of impact that are even until they encounter an obstacle such as a stick or wall and then the ripple changes not through our action but through interaction.
In life the interaction is caused by other people reacting to our actions who in turn toss their own pebble creating ripples that interact with ours. This then is the effect that is generated from our actions and it is definitely not a direct cause and effect.
We could then say that our present actions cause future possibilities that we could not of foreseen and therefore all our actions and expectations enter the realm of possibilities and not certainty.
In essence the expectations of the results from our actions are really much like throwing dice. Sometimes we win and sometimes we lose and there is rarely any certainty in life.