The biggest difference was a total change in my world view.

A short list:

More open minded/accepting of other peoples life choices and sexual orientations (that I now see as natural, not as sinful).

A greater appreciation for the planet and all its inhabitants. I even made peace with spiders. I still don’t want to pet them, or anything like that; but I am catch and release or let be if the location allows for it.

A greater appreciation/love for science. I have spent hours and hours learning and loving the science I was taught to fear and ignore.

No more worries about people going to Hell--especially good people.

No more struggling with why a supposed loving god allows so many horrible things to happen—especially to children.

Guilt-free Sundays...

*I realize not all gods are the god I was raised to believe existed; but this is the idea of god I was able to let go of. In learning more science, I realized that there is no evidence for any kind of god; and no god, of any kind, is necessary.

With all I gained when I became an atheist, it was still a long, difficult, process.

The most painful difference was that I lost a connection with family members. The toughest being that with my mother and daughters. It isn't like my relationship with them is bad, it is just different because we cannot discuss certain topics anymore.

I also lost a certainty about the planet (ignorance can be bliss). There was a certain comfort in believing we didn’t have to worry about the future of the planet because Jesus was on his way back and it would last as long as necessary. And, of course, I was going to get raptured before all the bad shit hit the fan.

*This said, I could not, and would not ever want to, go back to being a believer.
I prefer reality and knowing that we have to get our own shit together, individually and collectively.

I feel so much more logical and reasonable.

It has freed me from “duty” to try to lead others to Christ—and from the fear my fun-loving friends were going to hell.

Freedom from the scare tactics of religious fanatics and preachers. I no longer fear death, and "Hell" whatever that is. To die is a return to the way it was BEFORE you were born, or, to put it another way, as if you were NEVER born. We live on in the memories of those who knew us and loved us. I am much more secure in my own existence. And happier.

“To some people return to religion is the answer, not as an act of faith but in order to escape an intolerable doubt; they make this decision not out of devotion but in search of security.”
― Erich Fromm, Psychoanalysis and Religion, 1950

It has enhanced my love affair with the truth and reality, and thus made it easier to solve real problems for myself and loved ones.

I saved a lot of money by going to atheism.

That's not the reason I'm an atheist, but it is true.
I'd say freedom from manipulation by clergy and other religious fanatics is the biggest difference.

It freed up my Sunday mornings.
I feel no guilt when I decline to attend weddings and funerals.
Baptisms don't even exist in my life.
It's amazing how much time that nonsense requires of people's lives.

When I was still living under my mother's roof, I was expected to attend
mass every Sunday morning, with my younger sister.
My mother and her husband didn't go, but they made us go.
I was around 11 or 12, when I figured out we could skip mass, go
across the street to Dunkin' Donuts, and use the collection money
to have breakfast. Did that until I was 15 and quit going to church.
I'd go in, grab that week's program (to prove we'd gone), and duck out as
people were still coming in.
Unless my sister ratted us out to her before she died (well, just me, because she'd say I "made" her skip church--my sister was little snitch), my mother never knew.

Less guilt/more self respect. Not to mention understanding real guilt when I've actually done something wrong and being able to make better choices because of that. It hasn't been an easy switch (those negative mentalities are deeply embedded) but it's been a rewarding one. I just feel so much better about myself.

It has allowed me to see how controlled by myth we really are and given me total freedom on so many things. The scales were removed from my eyes and like Johnny Nash, "I Can See Clearly Now."

Freedom from fear and a peaceful satisfying life.

It's taken away a lot of guilt for having normal human reactions to normal human situations.

Instead of thinking I had to strive for absurdly impossible religious "perfection," and that I'd be judged and meted out rewards and punishments accordingly, I see every good and bad deed as rewards and punishments in and of themselves, to be dealt with on a case-by-case basis.
I still have my same strict conscience and same high standards of right and wrong, but I'm easier on myself when I screw up.
After all, I only human.

I am living in a real world instead of a fantasy world.

..can’t really describe a ‘known’ difference, as I’ve been atheist all my life. I’ve suspicions, though. Instead of easing into social acceptance and offered a career or a wife by whatever church I’d have joined, I tossed my ‘privilege’ and lived outside religion. There, you earn it!

Far more difficult in the day to find a mate/ wife not soaked in religion. Thus that pool was somewhat shallow.. Learned there were organizations I could not be a member of. Realized I could not be elected, or perhaps hold office as an ‘open atheist.’ Though ironically, my Atheism drove (and continues to drive) my political involvement(!).

For the most part, atheism was a life-long filter. Kept me from linking with people, organizations and institutions based on lies.. And with time, it’s proven itself to be 100% accurate, freeing, and allowed me to appreciate a higher level of consciousness - guilt free

Do whatever I feel right for me

At age 13, I became an atheist when I realized the Bible is just a book of stories written by men. "I decided I'm an atheist," I told my mother.

"That's fine, honey. I became an atheist in nursing school when I realized a woman cannot be turned into salt," she replied dryly and laughed.

Repercussions:

1. My cousin, a Jehovah's Witness, cut me off when she realized she could not convert me.

2. Through a dating website, two men tried to convert me.

"Martin Luther said there are no atheists," one guy said triumphantly as if that settled the issue.

"I don't care what a Catholic monk said 400 years ago," I replied, standing up. "Thanks for lunch. I'm leaving. Goodbye."

I have been an atheist since I was 15, 52 years ago. Apart from setting me up as an occasional target, atheism itself has not changed my life, but whatever was within me that allowed me to understand that there are no gods also allowed me to indulge in critical thinking, which of course influenced how I have lived and am living my life. It also allows me to curse at auto-correct as it repeatedly attempts to change "gods" as I type it to God's with a capital G and an apostrophe.

g

I'm able to have open and insightful philosophical discussions with people, without fear of blaspheming.

Being "me" just as I am has been a huge release.

I have more free time on Sundays!

A group I can be open and honest with great people here

I've been an Atheist since I was 9 or 10, being an athesit is god for because I'm a contrarian by nature

It honestly feels extremely relieving. Rather than have to justify everything I say or do with a ridiculously old book, I have the freedom to act how I think is right. I don’t have to hate gay people just because they’re gay and I don’t have to revere other Christians solely because they’re Christians. I can judge based off of people’s actions rather than their religion which means a lot to me. I also can recognize that not everything is my fault. If something bad happens to me, it’s not because I wasn’t praying hard enough or because I did something to deserve it. It just happens. Sure, it still sucks, but I enjoy not having to blame myself for everything anymore. I am a lot happier now that I know that things just happen.

I don’t think being an atheist has had any real impact on my life.

Guess I'm ignostic, not hurt by the label anyways. I understand clearly how Religions, military and politics emerged together to over power and over control the masses of people. Discovering many other strong individual entrepentures like myself is enlightening.