What the Jehovah's Witnesses fail to remember is the Scripture where Jesus said that the outbreak of the Great Tribulation would come as a thief in the night. Obviously, a thief in the night does not reveal warning signs that he is outside of the window about to break in. He comes in a manner which no one saw or even heard him coming. But, I suppose this fact is inconvenient to the JWs apocayptic anticipations.
What JWs also forget to bear in mind is that the Watchtower has repeatedly stated that the Great Tribulation will begin with the destruction of Babylon the Great; which is all of the world's religions. The Watchtower has stated bluntly and unambiguously that this attack on Babylon the Great would be "sudden", and "without warning".
Jehovah's Witnesses want desparately to believe that all of their sacrifices to the organization were not for nothing. They want to see something tangible which validates their lifetime of toil and allegiance to the Watchtower. They have paid their dues, now they want the "pay out".
They fail to remember that the Watchtower followers of the 1920s held the same expectations. As they looked around at the horrible depression of the 1930s, and then the outbreak of World War II, they were convinced that their "reward" was imminent. At that time in history, it seemed as if all of the evidence around them was obvious; right?
Those who fail to remember history are doomed to repeat it. If there is any group that has been such tragic example of repeating the same mistakes of the past; it has been the Watchtower and it's followers. Just like the gambling addict who keeps pulling the lever of the slot machine; Watchtower Witnesses continue to cling to the expectation and anticipation that their worship will be rewarded with utopia.