I left the Catholic church because of its knotweed of misogyny, prejudice, abuse of power, abuse of children and adults, and the church's view on same-sex unions. Pope Francis has pushed the boundaries on same-sex unions and this is a great achievement, but the backlash within the Catholic church itself is enormous and will possibly pummel his good and loving intentions.
I left about 5 years ago and it was an enormous bereavement. I felt very much like I was wandering in the wilderness, void of spirituality or guidance of any kind, lost underneath godless skies. I'd truly, truly lost my spirituality in a way I hadn't realised one could. It had been eroded by years of rhetoric and dogma spouted from the pulpit of the church I attended (it is fair to say that not all churches and not all priests are the same! I just happened to cross paths with a priest who would aid in altering my view of my religion- highlight the negatives of Catholicism). That dogma, those rules, and regulations really went against my beliefs, and boy, was I bitter. I felt very sour.
I did a lot of soul searching. It took time. When I realised that changing faiths was not the answer for me personally, I began really digging deeply to find out what faith and spirituality truly meant to me - did faith and spirituality have meaning at all in a life that appeared void of meaning and hope at times? Eventually, I realised, 'there is a crack, a crack in everything. That's how the light gets in,' and all that kind of stuff that moves you when you're in the midst of an existential AND spiritual crisis. What a Venn Diagram that would make!
For me, there is a singular story in my family history that really defined the difference between religion and faith. My grandfather was an Irish Catholic. He was born in 1902. And back when he was a young man (I'm not sure when exactly because this is a story that's been handed down), his Protestant friend had died. As a Catholic, he was not allowed to enter the church and attend his friend's funeral. As a man with human heart, as a friend, above all, he put his religion aside and walked into that church and took his seat in the front pew. It was a statement. I am sure many an Irishman did the same! But it was straight from the heart and it was him declaring love- and true faith in that very love- over religious dogma. He was being a true Christian, you could argue. And that to me defines what 'it's' all about, really. You just do the right thing, right? Treat others as you yourself would want to be treated. You don't need ANY religion to know this. And yet, EVERY religion does teach this- in between all the bits o' crazy. 
Be nice! You don't need a Good Book to tell you.
As for myself, I've explored all faiths, with great respect and integrity in my search. Because of my family history on dad's side, Judaism seemed like a natural 'next step'. But in the end, it was not at all for me. I realise that I am Christian, in my faith, in my thinking, in my philosophical approach to things- with elements of Humanism, Buddhism, Judaism, and Islam thrown in for good measure. They all bring something to the table. I think we all have different aspects of faith influencing our approach to living life. We're just not always aware of this.
My prayer comes easily to me again (which was something I had lost). And my temple is the outdoors. That sounds corny. But on my daily walks with my dog, I have chosen sanctuaries where I walk and think and pray and cry and submit to what cannot be changed and hope for the world that can be. I feel a spiritual flame within my womb at all times and I really try to tap into that feeling, that reality that we are part of something miraculous, beautiful, sad, and fleeting called life. And its force lives within us. It's glorious when you tap into that. It really is a lifebuoy of sorts. That is, for lack of a better way of putting it, God, imo.
Sorry to ramble on. Thank you for reading, if you did.
Coffee time and school runs are next (I've been up since 4am trying to rescue my cat from our neighbour's ridiculously HUGE tree).
I've enjoyed everyone's beautiful interpretations of faith and religion as well as great, personal insight on this thread. It is indeed a very personal journey.