If they have any misery it is for those trapped and fallen, for those battles fought hard and mighty only to see the victim run back to the enemies camp. But the victories of those who come out are sweet and souls are rescued...they know how to celebrate Christ's victories in this, and with it are humbled for having been an instrument in God's hand.
This is not a life of misery at all in how you define it....rather one of great Joy for having made a difference in the Lord's work to seek and save those who have fallen.
But God and the Evil One have been locked in this battle for as long as time has existed and beyond.
We reach out to the victims of this war, those that have been pushed on paths that do not lead to the Glory of Christ with love and compassion and bring them home to the father.
As for the witting or unwitting foot soldiers of the Evil One however, we must never forget that is out and out warfare, not a pillow fight. Serve evil and expect to reap what you sow and do not expect the Christian to stand down...
Turn the other check is for our brothers and sisters in Christ, not for those from outside who attack him...
If some Christians do not have the stomach for such a fight, it is understandable, but do not stand in the way or worse, help those who in turn are attacking the very Savior and faith you profess to adore...