My mum's nearly 70 and once as a kid got told off by her neighbour for reading a book on Good Friday, and even at the time her family thought that was extreme and ridiculous.
Have to admit the theatre threads are one thing where I do agree with MN. I don't go loads but I've seen a few shows since they re-opened and there's always people who have loud conversations, block people's view by holding up their phones to film (even though there's an announcement at the beginning saying it's not allowed) and try to speak/sing the lines along with the cast. At one show a group of drunk women were making so much noise they got kicked out, and they threatened and spat on the ushers who were telling them to leave

The police got called to the play in Manchester for the same reason, people being violent towards staff and vandalising the theatre when they were told to leave. I don't think people should have to sit completely motionless and never whisper or rustle a sweet packet, but stuff like this is so disrespectful to the cast and the rest of the aidience, especially families who've probably paid a fortune to be there.
Obviously 95% of people are great and don't do any of this but it only takes a handful for everyone to have a shit time. I accompanied a school trip to a performance of a GCSE text recently, so the audience was 80% teenagers, and they were so much more polite and considerate than some of the adult audiences.
Sorry, I know I sound like a proper grumpy old lady

It's just something that really pisses me off.