Growing up in an environment of logic, I found it difficult to follow religion as I grew older. Although part of my family was a believer, I began drifting away as religion couldn't answer all my questions satisfactorily. In the years, I've compiled my list of personal favorite reasons to not follow any religion.
1) I Have to Worry Only About Myself
All the religions have a similar tagline 'God is watching you at all times'. This implies that an entity non-existent in the physical dimensions is watching me at all times do things I am doing either privately or in public. How is It watching me/ Why is It watching me/ What purpose does this 'watching' serve?
This thought single-handedly consumes the efficiency of a person providing him with thoughts of guilt and a so-called belief in the unknown. Being an atheist, I know that I'll get the output of whatever input I give without the worry of someone invisible watching me at all times.
2) I Don't Need to Go to Church/Temple/Mosque/Gurdwara etc.
I save time in going to religious institutions and can invest the time in other activities. My confidence has increased tremendously since I became an atheist. How? The mindset that, if I go to God's house and pray, He will perhaps listen to me and grant my wishes is one of the most dangerous thoughts in the world.
A man can lose confidence in himself by believing that an invisible force can grant him a coveted job, promotion, house or a good wife etc., without putting in the required work input. By believing in myself, I know I am responsible for whatever happens in my life.
3) Which Religion to Follow?
There are so many religions in the world, each claiming to be the true one, passed on to humans by the messiah of God himself. There is no problem in that, except one of the core beliefs in every religion is that other religions are false. Each religion has a set of beliefs that contradict other religions.
Looking at this scientifically, it's quite obvious that all cannot be true, but, they can all be false. Each religion is strongly defended by its followers and any children born within the families of followers tend to impart their own set of beliefs onto the young ones.
In majority of the cases, it turns out the children follow the religion administered to them. Such sort of brain washing in my belief is a form of child abuse. If God, really did exist, he might want all to follow the same religion and not a diverse implications of his form in the minds of the people.
4) No Evidence of a Superior Being
Even though all religions exist, there is no such scientific evidence that will favor anyone of them. Books written in the ancient times were by people who didn't have an understanding of the scientific aspect of the world.
They were mere observers when they wrote the books, with no evidential backing to support their claims. These books are not worthy of being taken seriously even if they have a fan base of millions. Many superstitions are still followed all over the world which is laughed upon by people from other countries.
Religious followers all the time ask atheist's to prove the non-existence of God but are in a fix when asked to prove the existence of God. So if no one can satisfactorily provide evidence of existence, why follow?
5) Saving on Time and Energy
It amazes me on the amount of time religious followers spend in supporting their beliefs. They pray, chant, preach, sing hymns, bow, mumble, kneel, make unnatural movements with their bodies, wear special garments, lockets, do fast, visit swamis and gurus, visit extremely hard to reach 'religious' places, do pilgrimage, rituals etc.
But is there any evidence that these activities promote the personal well-being of a person and give positive results? No. Many disasters have occurred in places of religious worship, followers have been brutally murdered, exposed to accidents and natural calamities. The time and energy spent in such activities is tremendous but serves little purpose.
Recommended Reading: The God Delusion by Richard Dawkins