If you believe you are living a fulfilled life as an Orthodox Christian, well, good for you. But that's not the experience of many other practicing Christians. Religion teaches that all sorts of things are commanded/forbidden (examples: you have to fast, at times strictly, for over half the year. You have to go to church every Sunday and religious holiday if possible. You have to love God. You must not have premarital sex or even masturbate. You must not practice homosexuality. You must forgive people who hurt you...and so on and so forth). If you willfully refuse to do this and many other things, you are damned. Sorry, but this is what the church teaches and there are people who take this seriously and practice it. On the other hand, an atheist, who doesn't believe there is a sky goblin who can punish you for these so-called sins can do what he wants, as long as they don't hurt other people.
I agree that all these requirements and restrictions (or prohibitions) may annoy any rational human being, but only if they are taken out of their context. The "context" is, however, that all of us are "naturally" inclined to think that we are "good." Yet, also, if we are honest with ourselves, we see, pretty much all the time, that there are some seemingly simple things that we all find to be right, proper, decent and important to do - but we don't quite do them! C.S. Lewis writes very well about this in his book, "Mere Christianity." He says that we all agree with some sort of "universal law," parts of which are, for example, "I gave you half of my orange, so I expect you to give me half of your apple," or "this is my seat, because I came here earlier than you," or (more generally) "we must be fair in our relationships with each other." Indeed, writes Lewis, if we all agreed that these parts of the universal law are nonsense and should be simply ignored, we would turn into a bunch of fighting animals. But then, why is there so much misery and suffering around? Why, "knowing" that we all ought to be "fair," we are in fact so unfair that we engage in gossip, lies, violence, abuse, wars? Why over 3 billion people on this planet starve? Why GULAG, Auschwitz, Abu Graib? Why children are raped every day and hour?
The Orthodox Church answers to these questions, pointing out that we aren't "naturally" good. Our hearts are burdened with what the Church calls "passions" - unnatural, perverse use of all those mysterious "energies" that sustain our lives. We are born with a very natural inclination to enjoy delicious food and wine - and we become passionate gluttons and drunkards. We are born with a perfectly natural inclination to enjoy our partners in marriage - and we become passionate lust-bearers and adulterers. We are born with a great, glorious, wonderful natural inclination to dislike evil - and we become haters of the imagined "evil" in our brother. I am deliberately talking about extremes, realizing, of course, that not all of us do really reach such a condition when we eat 70,000 Calories a day, drink ourselves to death, cheat on our spouses, and murder our neighbor. But we have something in our heart, in our inner self, that might turn us into full-blown alcoholics, drug addicts, pathologically obese gluttons, adulterers and murderers, if this "something" is unchecked, if we do not struggle with it every day.
The Church teaches that the "passions," which are the real "engine" behind our transformation into horrible monsters, cannot be "cured" merely by education, or by economical improvements, or by changes in the social order, or by "liberation" from taboos, or by any other man-made, "natural" measures. And it is hard to disagree with Her: indeed, we see passions going amuck in all societies, in all economic strata, in groups whose education varies from zero to Ph.D., etc.
The Church also teaches that it is possible to become masters over our passions, but not by ourselves; we can conquer the passions by being joined with the Source of these mysterious "energies" that are meant to sustain our lives and that we "naturally" misuse. This "joining" occurs when we gather as a community, a body of people, and become united with each other by the mystery of mysteries, which is called the Holy Mystery of Eucharist (Thanksgiving). When that happens, this Source of every possible energy, activity, life actually lives WITHIN us and helps us, guides us, purifies us, makes us into something that is like Himself (and, again, our theology teaches us that the only thing we can say about what He IS is that He is Love).
Now, prayer, fasting, chastity (in the life of singles as well as in marriage), forgiveness, charity (almsgiving) - yes, all this is important, but ONLY in the context of living within the divine Body (the Church) and living WITH the Source (or, as we say, King of All) in us, for the purpose of becoming masters over our passions instead of gradually degrading and turning into the passions' prey. If we do all of the above as some sort of "magic," i.e. expecting that we will get some kind of "payment" from God merely for ritualistic doing of all that, we always get sorely disappointed: our passions only increase their dominion over us.
We are never perfect. We stumble and fall all the time. But sometimes we do notice that as we continue our journey within the Church, something changes in us. We should not be overly enthusiastic about this, boasting, trumpeting our virtues. And yet, we have examples of great saints, of people who lived truly righteous lives, literally radiating light, love, kindness, humility, holiness.