What is the best profanity filter for Firefox that is free?

I get so tired of searching for things on Google that are perfectly innocent and I run across a really bad word in one of the search terms. This has happened to me numerous times. I have tried ProCon Latte, but there were some features I didn’t need on there. I’ve also tried some scripts for Greasemonkey, but they weren’t working too well. I just want something that will block out all of the bad words on the internet, including Facebook. I hope you don’t think I’m crazy for asking this.