I find this an effective tool not only to tide over a bad phase but also to be prepared for an abrupt end of a seemingly happy phase. It is not easy to keep ruminating this especially during the happy phase. It is only when I fall with a thud (figuratively) that I curse myself as to why I did not keep myself aware? And, the cycle continues.
What I have understood of Vipassana Meditation is that it inculcates in us an observer’s perspective in dealing with our emotions. It is particularly helpful for people who do not like to give credit to God for the good times and hold Him responsible for the bad times. For me He is just a person whom I like to call only when I get nature’s call (s) at any ungodly hour, otherwise I like to leave Him alone with his duties of running this world.