What is "pissed"?

That's, sadly, the question I got from my eight-year-old daughter near the end of the last episode as we watched "The Biggest Loser" this week. You can't watch much of evening TV these days (even a silly reality show about losing weight) without having to counsel your kids.

Why does our language in this culture have to keep degrading? Where will it end? How can we as adults set a high standard for cleanness in our kids' language when we feel our own language slipping?