The reason for suffering is that we need resistance in order to build character. Without resistance, you cannot build muscle; without temptation, you cannot build character.
We must understand the importance of suffering. We must recognize that we cannot be brought into Ultimate Reality until we have fully matured. We must become like Ultimate Reality.
Consider the egg. If you help a chick break free and prevent it from struggling, you will kill the bird. It needs that struggle to develop the strength required to survive. We are no different.
Or consider the caterpillar. It forms a chrysalis, and within that confinement it becomes a butterfly. If you break the chrysalis and release it too soon, it will die. We are the same.
We do not like struggle. We do not like suffering or temptation. Yet these are necessary for the formation of character, and character determines destiny. We must become like God, like Ultimate Reality, and the only way to do so is through suffering.