The answer to most of you will appear nonsense while some might find it funny and few rare souls might find it great.
Before I tell you the answer let me teach you some physics mainly mechanics. I know it is boring but if you are keen observer then you might appreciate the thinking.
Suppose, a box is moving on a surface. If a person, who don't know anything about physics, is standing on ground. He will say that box is moving on ground. While a person sitting on box will say that earth is moving.
Now it could be concluded from this, that a novice gives correct answer when he is not sitting on box. However, if a person, who knows physics, is made to observe the situation by sitting on box. He will conclude the correct answer as he knows that the force direction which appears when he is sitting on box is a false force (or, pseudo force). So, he rectifies the direction of force and can get correct answer.
Now, same is the case we face in our real life. If we are in the problem (i.e., on the box) then we will conclude a wrong answer unless and until we are intelligent enough to conclude that the direction is wrong. While if we are not in problem and then even if we are novice to that problem we can still solve that problem with success because we don't have to deal with false forces or pseudo forces.
Now, I think that you have got the answer that why it is east to solve the problem if we are not involved it. I think the possible reason why the above phenomenon exists because if we are not involved in the problem then we know that we have nothing to loose and probably this thinking help us to think rationally. So, in short, toughness of problem depends on your frame of reference.
