For me, the Tower represents an unexpected change that one experiences as being a disaster at the time. It usually is the breakdown of something one thought was secure in your life. There is a period of insecurity that follows, wondering if other things you thought were secure could fall apart also. There is a light at the end of the tunnel, though. One usually moves on to a much better place that wouldn't have happened if you had stayed in that secure structure.
Could be a relationship that that you have outgrown, but would never have voluntarily left, a partner that you never would have dreamed would abandon you who suddenly walks away leaving you feeling very vulnerable. Eventually, though, you find a more fulfilling relationship that you wouldn't have been free to enter into if the old relationship hadn't broken up.
Could be a boring, but secure job that you perceived as being worth staying in for the insurance benefits, sick days, stability, etc. Then, unexpectedly you are layed off or fired. Again, lot of insecure feelings, but then you move on to a much better, more fulfilling job that you never would have considered taking if you hadn't lost the previous job.
The Tower is a good card, it just takes going through a dark patch before you receive the rewards this card offers.