Telling someone they can't be serious is moving from discussing with an open mind to nearly telling someone they're wrong. Challenging an opinion is different, that's using words like 'I think' and 'I feel'. Not using statement like 'this is'. As you did.
"I think" that's none of your business, and "I feel" that this is a discussion board and not some kind of waldorf school. Better?
And you're telling me to get a life.... Hell, it's funny that I was the second one making a comment about what teachers are teaching us and you're picking me to comment on. Kinda flattering really. Thanks. 
