At some point, I made a distinction between the two, which I've never stopped to explain to anyone.

Yes, I'm one of those people who might say "I'm spiritual, not religious." Here's how it happened:

My parents generation uses the word religious, to describe a church-going person with Christian beliefs. When my belief (and church attendance) decayed, and I became atheist, I rejected all of that. Spirituality and superstition were lumped in there somewhere I assumed.

...and then I found some pagan practices I could believe in. This challenged me (and still challenges me) to define what I am. My starting point was Wicca, organized into covens, like a resistance cell structure. there's no church to attend. A lot of neopaganism isn't even that. It's disorganized individual practice. there are many people (like me) who might as well be a religion of one... what do you call that?

Spirituality.

Over time, I've found religion is rarely true spirituality. You can talk about religious belief all day long, and it feels like rolling in the mud with a pig. Circular logic, tired old theology, obscure Bible quotes, and so much anger. So many words used to mean nothing. The kind of wisdom that makes one rethink their life, find a way to improve it, and inspires you with the energy to follow through isn't to be found there. And it usually can be said with far fewer words.

And this is how I would define the two:

Religion is finding truth in only one particular book, and rejecting all others.

Spirituality is finding truth everywhere, from other religions, famous quotes, popular songs, stories, video games, and even the words of atheists.

Religion is believing there is only one correct way to pray.

Spirituality is trying out many rituals to find what works for you.

Religion is calling upon a priest of your faith to cleanse supernatural evil.

Spirituality is learning how to sweep out your house yourself.

Religion is telling people their beliefs are wrong and yours are right.

Spirituality is listening to others and when they say something wise, taking it to heart.

Religion is condemning people because an obscure line in a forgotten paragraph of your holy book says to.

Spirituality is comforting people who have been mistreated for bullshit reasons.

Religion is writing a 10,000-page rant about why science is wrong (and your holy book is right.)

Spirituality is learning all you can about the universe and our place in it, and making truer beliefs from that.

Religion is bowing to your god at specific ritual times regularly, muttering rigidly structured prayers, and making the expected offerings at their shrine.

Spirituality is standing before a god, getting to know them, and maybe giving them a gift or two if you like them.

Religion is protesting a funeral.

Spirituality is attending a funeral.

Religion is blowing yourself up to reach Heaven.

Spirituality is building yourself up into the best person you can be in this lifetime, Heaven or not.

Religion comes from fear.

Spirituality comes from joy.