Argh it drives me insane but I do think it's only good manners to teach your children to eat with mouths closed.
Small family members aged 7 and 9 have both started to eat with their mouths wide open and, if that wasn't bad enough, they smack their lips with every thunderous mouthful. The parents say nothing about it. I have asked said children to eat with their mouths closed as has DH. How can the message be politely and civilly put across without me exploding in a completely irrational manner?
I have to point out that i can't bare to hear people eating but even my calm husband and tolerant children think it's disgusting.