Occasionally. Old language habits die hard.

No different than saying "oh my god!" during sex.
It's like swearing.
They're just words.

Because "Thank science" or "Oh, my reality" just don't have the same ring. I do it too, fully aware of the irony.

Edited to Add -- You are from Quebec, I see. I instantly thought of this.

I also say "I'll be back," even though I don't believe in the Terminator. They are just part of our shared language.

just like saying any other common words...just because you say oh shit doesn't mean you did...

I still say it, but it's out of habit! Lol

I say it because I hear it all the time. My Mom still gets pissed if I let it slip in front of her though because "it's a sin" or whatever.

If I am not allowed to say it when I was religious, no one is going to stop me now.

Just a group of words I give it no second thought it matters not anyhow

It is just part of our lexicon. We say Hell all of the time even though it does not exist either. We eat devil's food cake. We say the devil is in the detail.

Yes, sometimes by habit.

It’s alright, but you’ll have to do ten push-ups while saying “there is no god!”. On the other hand you could just crack open a beer and watch South Park.

How about Jesus fucking Christ? I say that

I use "Oh my Glob" from Adventure Time.

I know, when I say "bless you" when someone sneezes, I think what am I saying!

I use figures of speech and colloquialisms all the time. But I've never actually ate a horse, hit any hay, and still don't believe in deities.

When dropping a can on my foot in the supermarket, I hear the guilty by standers snicker when I say "Fudge sickles!" or same sounding oaths. Just naughty enough for them say "Huh?"

Took me a life time to get out of the habits of the more common oaths like saying "thank God" for jalopenaia!

It's just a habit. I'm trying to stop negative self-talk and swearing.

Oh my God seems like the right thing to scream during sex

Its just words, not a proclamation.

As with everything else, religion has co-opted and dominates even our language.

I catch myself using religious terms but I try to avoid that. I don't want to promote religious myths. I try to say instead, "Thanks goodness" or thank you Zeus".

But, what about something in us, that is more than our consciousness? A psychic part, I could easily call that a ‘god part’ of my own nature. Because, often times I have things happen that I could never have experienced before and could not have a memory of! We can thank our ‘higher self!’

IMHO, they are just saying out of habit.
There are myriad of other common sayings that have came from other meanings, most we don't even know where they came from.
I've seen some literature on the origins of many sayings, but honestly none come to mind at the moment, although I might just look that up again.
So, I really don't put much weight to hearing, or saying them.

Invoking God has crept into our language similar to the way Heil Hitler crept into the German language it is an expression.
I am told that it is a special sin offensive to Christians good.

Cultural conditioning.

Of course, I watch a lot of Futurama reruns, so I often say, "Oh your God!"