I think coherently everyone believes that choice is power, i.e. the more choices one has, the more powerful he feels. When there's choice as whether to go or stay, most people incline to go because this may put them in a position with more choices than just stay to getting old and fossilised.
Let's look forward so long as decision has been made. Yes Winston Churchill said "the farther back you look, the farther forward you can see". But that's purely to encourage us to fully understand where we are from and to be responsible for whatever decision we made. Trust me, we have been enpowered with more choices by CHOOSING responsibly to be here the new land. So, feel strong, happy and, complain less.