Calling people who don't agree with everything you do 'stuffed shirts' , even when you pretend to hide it, maybe one reason why you sometimes get negative responses.
The only thing I have every objected to is the trivialisation of serious topics - if you don't feel able to add anything to a topic, why try to derail it for other people? There are plenty of opportunities for light-hearted banter, but it is sometimes just not appropriate and I expect mature people to recognise the difference.