How can you make a decision if you’re omniscient?

I think the central message of Christianity is that I can have eternal life.  I wonder why I should even care about having everlasting life.  Everyone who lives long enough will get tired of living.Does God love/hate Satan?  In fact does God love/hate anyone?  It seems to me that another way of putting this is whether God can make a decision at some point to love or hate someone.  This surely in turn raises a thorny issue.  God is omniscient, and I take that to mean that knowing everything, he knows the future as well as the present.  Let’s for instance take Satan, who I think was God’s favorite angel in the distant past.  If God chose to love Satan in the past, then, knowing that in the future he, God, would hate him for some indiscretion or other, God’s behaviour would be irrational to a human’s way of thinking.  For one who knows the future, the only thing that makes any sense is to start out the way you mean to go on.  Having created Satan, presumably with the best of intentions, and love in his heart at that point, he would continue to love Satan to the end of eternity.  The same reasoning must also apply to humanity.  I guess that gives people, and Satan, hope that after a few million years in the “regions of sorrow, doleful shades, where peace and rest can never dwell, hope never comes that comes to all, but torture without end still urges, and a fiery deluge, fed with ever-burning sulphur unconsumed” (I love Milton), God might relent after all, but then he knows he’d do that too.  So my basic point is that being omniscient is incompatible with changing one’s mind.  How bored with life God must be!