A widely established part of practicing the Abrahamic religions revolves appreciation of not only what you have, but also what you have been given. You are often, if not always, told something along the lines of, "God gave you life and free will. And so you have every reason to be thankful."
On the surface this sounds perfectly reasonable: If it wasn't for God you would not be alive, you would not be able to enjoy life and if he had acted differently you may not even have had a free will at this point. For this reason you should never disrepect God in any sort of way. You owe him everything you have.
Personally, I wouldn't say that we owe him everything though. Even if some believers may say otherwise. I say that he merely gave us the tools: The Earth, life and a free will. Then we and everyone else on this planet used these tools to create our current situation. We owe him the tools, not our own creations such as our children, all the things that we buy and the result (happiness, sadness, etc) of every other action that we make. He made it possible, we made it happen. Thus, while God did create life, you should still go thank your parents for creating you, while solely thanking God for making it possible.
So, at this point we owe God the sheer possibility of making everything that we have possible, and it makes absolute sense to be thankful for that possibility.
...if you have anything to be thankful about, that is. I mean, millions of people have been born only to live through a miserable life. They may have died alone, lived on the streets, were forced to become prostitutes, commited suicide because of all of their misery and so on. Millions (if not billions) of people lived/lives through complete shit despite using their "blessed" free will only for good throughout their lives. They were never rewarded during their lifetimes, or at least not in a notable manner, and always thought deep inside that a quick route away from life would be better than living through the same shit for another 40 years.
And what is God's response to this? APPRECIATE LIFE! Life is a gift! Commiting suicide is a sin! You owe me everything you have! Don't disrespect me by taking your own life, accept the fact that you can't do anything about your situation and start appreciating life! USE MY GIFT! You don't want to go to hell, do you?
Now, at this point I can see one scenario in which case people still would side with God, namely the scenario where God put actual effort into making your life possible. If God actually went through blood, sweat and tears to make your life possible, then maybe it would make sense to show some respect in return. But the truth is that he didn't. God is almighty, remember? We are not the result of a thinking person working hard to achieve something, we are the result of an almighty being committing a random act which required no efforts whatsoever. Sure, the Bible says that he "rested" on the seventh day, but given how that would prove that he is not "fully" almighty I guess even strong believers would agree that that is complete bullshit, while all non-believers (well, and some believers) simply add this to the pile of contradictions found in the Holy Bible.
Thus, the only reason left for these people to love and worship God should be their desire to enter heaven, not out of appreciation for what they have. They have every right to complain about their situation, but should refrain from doing so in an act of selfishness.....
In conclusion: A person who lives through nothing but shit despite great efforts owes God nothing but shit. And God should not expect these people to appreciate the lives that they have been given. They could and should complain about God being unfair, but probably won't since they fear going to hell.
I'm not saying that miserable people finding comfort through God is a bad thing. All I'm saying is that God is unjust. What do you say?