Inspired by a discussion my boyfriend and I had last night.
I think I've mentioned in on the forums a few times already: My boyfriend is a practising Catholic while I am theoretically Protestant, but practically not religious.
I think it's basically a cultural difference. If my boyfriend wasn't Polish, he most likely wouldn't be religious either. For those of you who didn't know it and I don't blame you, Poland's not exactly the most important country from a global perspective: Poland is basically the stronghold of the Catholic Church in mainland Europe. For a number of reasons Catholicism has played a big part in Polish history and it's not surprising that a lot of them are still very Catholuc.
Coming from the protestantic north of Germany myself, I don't know anyone who'd attend church on a regular basis. Churches, even in rural areas are empty. Sometimes there's not more than 10 people on a Sunday. If someone went to church regularly, you could basically be sure that they were Jehovas' Wittness or in some other sort of sect.

My boyfriend and I both enjoy discussing our cultures and religions (or lack thereof) a lot.
I've asked him to explain to me why exactly he goes to mass and confession or why he considers himself a Catholic even though there's so many doctrines he doesn't agree with and gotten more or less satisfying answers. On the other hand I explain him how (my denomination of) Protestantism differs from Catholicism, why I agree with most of it or how I can not-believe in an afterlife.
Most of the time it's really interesting and insightful for us to talk about that things. However, last night he pissed me off a bit. Lent's coming up and in my church there's an action called "7 weeks without" and I really like the idea and have always given up something for Lent for past years. So I told him that I was choosing sweets this year and not eat them until Easter.
He basically said that he thinks it's supid and for little children to give up something like that. Now I wouldn't mind that at all, if he either didn't care about Lent at all OR was giving up on something harder. It's neither, though. He said something vague about reading the Bible during Lent or being 'a better person' without being concrete about it. I really couldcare less, but saying whatever I do is childish and meaningless when you're doing nothing at all, even though you consider yourself a Catholic?! Not cool.
But in the end he saw how what he had said could be disrespectful to me und I understood why he said it in the first place. While for me "7 weeks without" is the only form of practised Lent I know and most people over don't even do that, he knows a lot of people who go to church (almost) daily, don't go out (or when they do don't drink or dance). don't eat meat, etc etc. Giving up candy is apparently only for children in Poland.

Moral of the story: There's bigger cultural differences between our countries than you might think, we have great communication, I love my boyfriend and we'll live happily ever after.