You don't have to look far to find criticisms on almost every religion. Christianity, for example, worships the idea of human sacrifice as a way to free us from our "original sin". Not to mention that original sin doesn't make sense in the new common belief that Adam and Eve are only a metaphor. Islam, on the other hand, writes about the Buraq. This is the mythical winged horse character found in the hadith, which flies Muhammad to and from Mecca.
Besides the fact that religion has enough silly elements to make you skeptical, it also tends to have widespread impacts on our society as a whole. Here are a few examples.
Religion encourages herd mentality: All religions claim that they are legitimate, and a majority of the world participates in it. Moreover, religion often entraps you at a very young age, even in infancy through baptisms. As you grow up you think the world around you is normal. Eating the body of Christ and drinking his blood doesn't even seem odd, let alone inhumane. Well, everyone else is doing it, so it can't be wrong, right? Wrong! Most non-religious people choose not to partake in the rituals and are perfectly happy with their lives.
Can diminish the value in thinking for yourself: Religion makes us think we cannot be good without being following it. But when you start to give it up, you realize that you're exactly the same person. Some would argue that it makes you even more aware of your morality. Since you aren't spending time blindly worshiping a god, you can spend more time examining your actions and decisions. You can be more introspective, and not use God as an answer, or an excuse anymore.
Ignores the reality of the world: Scientists are certainly hard at work seeking answers to why we're here, what the universe is all about, and if life exists beyond our planet, religion continues to ignore the awe-inspiring reality we have found ourselves in. The bible does not offer any explanations about the universe, or the origin of life, aside from fables.
There are so many more reasons that religion just doesn't make sense. We're always finding more information, so be sure to bookmark this page to check back in the future.