Perhaps mankind's most reliable source of conflict over the course of history is religion. My god is better than your god, and I am going to save you from hell if I have to send you there myself in the process. Christians hate Muslims. Muslims hate Christians. Islam has a standing death sentence to anyone who abandons Islam for some other faith. Both Christians and Muslims hate the Jews. The athiests hate everybody. Everybody hates the athiests. Factions within a particular faith hate each other. And we haven't even gotten into the non-Abrahamic faiths.
Personally, I belong to a Lutheran church, which on a day-to-day basis is just about as low-key and laid-back a Christian sect as you're likely to find. Getting absolved of all your sins basically involves going to church. Sometime during the congregation, you will be relieved of all your sins. That is literally it. No Hail Maries, no pilgrimages, no tithing, no confessions, no real spiritual exertion whatsoever.
But Lutheranism isn't really the end of it for me. Along the way, I also picked up a belief in karma. Not really a pure good-deeds-lead-to-good-fortune, bad-deeds-lead-to-bad-fortune cause-and-effect-- there's far too much evidence to the contrary for that, and when it does happen, the proximity of act to reciprocation is all over the place-- but more of a system where your deeds get played against your well-being at the end, deeds getting more weight. Humanity gets a chance to sort it all out on its own, and then metaphysics accounts for any imbalance at the end. Which basically means the ones who got away with it in life get it the worst in the afterlife.
But more importantly, I feel that it really does not matter, in the slightest, what you believe so long as you parlay that belief into being a generally decent human being that can on some level get along with as many people as possible. In short, if heaven doesn't have room for Mother Teresa, Gandhi and Socrates, all at the same time, I don't want to go there.
It all comes back around to the Golden Rule, and no matter what you believe, if you believe, or where you come from, there is almost assuredly a Golden Rule for you. Some would claim that karma itself is simply an enforced Golden Rule. As much as the moral codes of all the world's faiths and cultures differ, the Golden Rule is remarkably- and thankfully- resilient.
Some present it multiple times, but we'll keep it to one telling per faith (as best reckoned)...
"Do not return evil to your adversary; requite with kindness the one who does evil to you, maintain justice for your enemy, be friendly to your enemy."
"Ascribe not to any soul that which thou wouldst not have ascribed to thee, and say not that which thou doest not." "Blessed is he who preferreth his brother before himself." (Baha'u'llah)
"This is the sum of Dharma [duty]: Do naught unto others which would cause you pain if done to you". (Mahabharata, 5:1517)
"Hurt not others in ways that you yourself would find hurtful." (Udana-Varga 5:18)
"Therefore all things whatsoever ye would that men should do to you, do ye even so to them: for this is the law and the prophets." (Matthew 7:12, King James Version)
"Tse-kung asked, 'Is there one word that can serve as a principle of conduct for life?' Confucius replied, 'It is the word 'shu' -- reciprocity. Do not impose on others what you yourself do not desire.'" (Doctrine of the Mean 13.3)
"Do for one who may do for you, that you may cause him thus to do." (The Tale of the Eloquent Peasant, 109 - 110)
"This is the sum of duty: do not do to others what would cause pain if done to you." (Mahabharata 5:1517)
"None of you [truly] believes until he wishes for his brother what he wishes for himself." (Number 13 of Imam "Al-Nawawi's Forty Hadiths.")
"A man should wander about treating all creatures as he himself would be treated." (Sutrakritanga 1.11.33)
"What is hateful to you, do not to your fellow man. This is the law: all the rest is commentary." (Talmud, Shabbat 31a)
"If people regarded other people's families in the same way that they regard their own, who then would incite their own family to attack that of another? For one would do for others as one would do for oneself." (Mozi)
Native American Spirituality
“Humankind has not woven the web of life. We are but one thread within it. Whatever we do to the web, we do to ourselves.” (Chief Seattle)
"Do not do to others that which would anger you if others did it to you." (Socrates)
“The law imprinted on the hearts of all men is to love the members of society as themselves.”
This one was founded off of Jesus' parable of the Good Samaritan. Need I say more? I mean, really?
"Try to treat others as you would want them to treat you." (The Way to Happiness, by L. Ron Hubbard)
"Don't be a dick." (http://meta.wikimedia.org/wiki/Don't_be_a_dick)
"Be charitable to all beings, love is the representative of God." (Ko-ji-ki Hachiman Kasuga)
"We obtain salvation by loving our fellow man and God." (Granth, Japji XXI)
“The basis of Sufism is consideration of the hearts and feelings of others. If you haven't the will to gladden someone's heart, then at least beware lest you hurt someone's heart, for on our path, no sin exists but this.” (Dr. Javad Nurbakhsh, Master of the Nimatullahi Sufi Order)
"Regard your neighbor's gain as your gain and your neighbor's loss as your loss." (Tai-shang Kang-ying P'ien)
"This is the sum of duty. Do not unto others that which would cause you pain if done to you." (Mahabharata 5:1517)
“We affirm and promote respect for the interdependent web of all existence of which we are a part.” (Unitarian principle)
“A'in it harm no one, do what thou wilt” (i.e., do whatever you want to, as long as it harms nobody, including yourself). (The Wiccan Rede)
“One going to take a pointed stick to pinch a baby bird should first try it on himself to feel how it hurts.”
"That nature alone is good which refrains from doing unto another whatsoever is not good for itself." (Avesta, Dadistan-i-dinik 94:5)
In conclusion, here's a guy that completely misses the point.