I was born an Orthodox Christian in a family of Orthodox Christians.
We're not particularly religious, as in, doctrinally. If I run into people who have names of saints like Andrew, micheal, vasile, etc when it's their saint's nameday, I say happy birthday or something like that. I say "Hristos a inviat / Adevarat a inviat" (what you say at passover when got revived from the dead)... I still know about 10 prayers which I learned when I was young though I haven't prayed all that much in my life.
Why am I still an Orthodox Christian? Because it's cool and there is no pressure put on me from my fellow Christians or other people. In fact, the most pressure I got was from atheist friends of mine. They're the only assholes who tried to mock me for my faith but I never felt pressure from other Christians to adopt a christian philosophy or to change my life because God wills it or because the Bible says so. It's also better than to be a jew and way better than to be a muslim and I don't fancy all those eastern buddhist, confucian, shinto and especially not hinduism. I read about them sufficiently enough to know I don't believe a word of them and for on in particular, hinduism, I'm quite virulent against it because it's the worst religion ever. But really, despite personal loss in life, I have never blamed God or that never turned me atheistic. Have I ever wanted to be another denomination of christianity? Not really... but that's because I don't see the point but I have much respect for all Christian denominations unless it's mormonism and those jehova witnesses... and some baptists in america.
Am I sure God exists?
No, I'm not sure, but I don't give it much thought. I have no evidence but I believe He exists and you know, the afterlife. I believe strongly that an afterlife exists. Or I really do wish it exists for personal motives. It's really the best part about Christianity in my opinion. really, if I had to pick 1 thing that keeps me a Christian is the afterlife, and mainly heaven and the chance to reunite with people you lost in life. I don't have a fear of hell as much as I have a hope that heaven is real. This is why I don't like all that buddhist crap with ressurection. Nirvana my ass. I don't want to spend my life in meditation. Life is about getting into trouble as much as it is about getting out of trouble. I don't want to have to restart the same game as it were, in the same world, when I die, and if you're a hindu, you'll revive as a cockroach if you've been bad. Yeah, like i'll beat the game as a cockroach... and cows, yeah, I'd win if I were to be revived as a cow in India, but get revived as a cow in a McDonalds farm... GG. I want to play a new game and yeah...
But despite all my personal views on other religions, really, if following a religion makes you want to be a better person... even if it's hinduism, you know, go for it. Be a better person. If following no religion makes you want to be a better person... fine, be atheist or agnostic. If you don't give a hoot, fine, but try and be a better person.