What should parents never do in front of their children?

On top of Hui Qun's comment, I sincerely believe a parent shouldn't fight with one another in front of their kids. If there is a need to, close the doors and soften your vocie. Or if this is impossible, one partner can leave the place for awhile until both has calm down to talk without screaming bloody murder. Another thing is, always treat service staff with respect. I think this something most parents forget about and it's just so said to see kids nowadays talk in such a haughty tone to a service staff. "Please" and "Thank you" are definitely a must.