www.merriam-webster.com/dictionary/sacrilege
Sacrilegious is often used in reference to religion, or to religious things, so it is easy to see why people might be confused by its spelling. However, sacrilegious and religious are not from the same roots.

Bacon on a bagel - You cannot get more sacrilegious than that

I told the local pastor that I thought there was very little difference between him and a drug dealer, that they both peddle false dreams, delusions and lies.

There is no such thing as sacrilegious.

wanked in the choir practice room during the Sunday service while it played over a speaker in the room.

Stuff like this. "Sacreligious" jokes. No more offensive than Monty Python, really.

Over the years as I got away from church I found that I was swearing like a sailor. (No offense to any sailors. It's just a remark.) Of course, I don't do this in public. It's a private thing. My younger daughter is just like me and I was not always around as she was growing up. Do you think swearing is genetic?

Back when I was young and forced to go to Church, I used to sit in sanctuary during Sunday services, look around, and fantasize about engaging in coitus with the pretty girls. I don’t know if this next anecdote counts as “in Church,” but one day I was cutting class and wandered the grounds of Mount Saint Vincent in the Bronx with fellow delinquents. Upon coming to a statue of the Virgin Mary surrounded by gates, we observed there were people who, I guess prayed at the statue, and threw in coins as an offering I suspect. My friends and I reached our arms under the fencing and helped ourselves to all the coins we could reach.

I’m a terrible blasphemer. Especially if I’m angry, hurt(like stubbing a toe, etc), or having an orgasm. ‘Jesus motherfucking Christ’ and ‘god fucking dammit’ are my faves: I need lots of syllables.

I went to a midnight mass one Christmas when I was a teenager. Many people went there straight from the pubs which closed at 11.30pm so I was one among many drunks. But I took it a step further by lighting up a cigarette in the middle of the ceremony. I was very brave when i was drunk and told anyone who wanted me to put it out to fuck off. I was very angry at the Catholic Church those days.

As Red says in Shawshank Redemption 'That kid's long gone, and this old man is all that's left'.

Given that I don't believe anything is sacred, I have to go with nothing.
If it's what others might think of as sacrilegious, I've got a list.
LOL

This doesn't qualify as sacrilegious per se. And I was only indirectly involved. But long ago I had a roommate and separately a friend who were both LDS . The roommate's girlfriend would spend nights in his bedroom but the rule was they would always keep one foot on the floor. Lol. (I never pressed for an explanation.)

They would go to Wed. night dances at the local church.
One time a couple of girls we knew were curious and wanted to see it and to find out what Mormon girls were like. They practiced for days to be able to talk without accidentally shocking the sensibilities of the poor pristine Mormon girls.

Everything was fine (but understandably slow) until they went to the girls' room for a break. They came back red-faced. They couldn't believe how dirty the religious girls talked when guys weren't listening. It was a huge eye-opening experience for both of them.

I figure people, especially kids, are pretty much the same everywhere. The problems mostly come up when people try to apply their own expectations on others.

My Aunt , Uncle and cousins were Catholic . Their normal curse was , Mary , Jesus , Joseph , and Christ .

One day, when I was in first grade, my mother forgot that it was Friday, and she sent my brother and I to school with bologna sandwiches for lunch. So, I ate meat on Friday, at a time when Catholics weren't allowed to do so. Honestly, I didn't lose a wink of sleep over it.

I have no idea because I have never been religious. I guess my existence will suffice.

I wore tennis shoes.shorts and t shirt to church on a sunday.

Note: in the black culture that's unheard of.

I told a relative to go to hell......I was 7.