In no particular order.
1. - Christianity. A million different sects, all with their own rules and beliefs. Most of them incompatible with each other. You don't like black people, or Jews, or gay people, or people that drive Volkswagens? Then there's a Christian sect for you. And they're all right, and you are wrong. And they love to tell you about it. Loudly.
2. - Atheism. The religion that revolves around telling anyone who believes in anything that they are wrong and that life is all a huge coincidence. They believe so strongly in their non-belief that they feel the need to shove their non-belief on to everyone else, thus making them a religion of non-religion.
3. Global Warming Eco-Freaks. The religion of decrying the evils of man and their planet killing technologies. Al Gore is their pope, and you are an enemy of the planet. Never mind that scientific evidence tells us that the Earth warms and cools in cycles and has been doing this for millions of years without mankind's evil. No, it's all because of US and we're all going to be EXTINCT!
4. Islam. - Almost any religion is about controlling people and getting them to act the way that you think is appropriate. Islam is just a lot more open about that, and is in control of a good many governments throughout the world. You know, friendly, happy places like Iran, Sudan, and Indonesia. Combine the countries controlled by Islamic law with the actions of groups like the Taliban and al-Qaeda and you can kind of see why Islam annoys people.
5. Democrats and Republicans. Oh, come on. You know that you are religions. Your followers believe everything you say, and try to convert people from the other side. You both take offerings from your followers, promise to take care of them and lead them on the path, and fleece them like a televangelist with a million dollar gambling debt.