The Millennium Falcon fled across oceans of space and the man in black followed. Borrowing heavily from Stephen King, this is why I consider Empire Strikes Back far and away the finest of the Star Wars films.
They hideout in the snow and ice. They are relentlessly pursued and found. They flee again and Han Solo is ultimately captured. There is no happy ending in this one, only hope. This is perfection.
This is like life for roughly 7.6 billion of us. We struggle and persevere, never quite achieving what we would call “success” (safety?) But, there is always that hope. As long as we are still breathing, there is hope for something better. This is a great place to be. Trust me, you want more tale to be told. To reach the end, even in triumph is emptiness and loss. As they say, perfection is unattainable and that is perfection.
Maybe that was a bit deeper than I intended it to be. I merely set out to explore my own thoughts and figure out why I like Empire best of all. 
This is where that journey took me. Maybe I’m still struggling to get to the bottom of it. The simpler answer is that there’s no joyous celebration at the end complete with “mission accomplished” banner. As Luke and Leia stare into the vastness of space contemplating their future I am left feeling unsatisfied. Unsatisfied, but happy and ready for more.
Do yourself a favor…watch Empire Strikes Back again. Watch it for the first time if that be the case. Really enjoy it this time. Revel in it. Hope that it never achieves it’s goal (The End?)