Alex Duffy, a morning radio DJ in the UK, told his co-anchor Emma Louise Jones that he was going to review a list of swear words that had become socially acceptable. The beautiful twist is that they were not actually on-air, but she absolutely thought they were live. Nothing beats a classic radio prank. Based on her reactions, he must have dropped a few that are truly unfit for broadcast (although they're bleeped in the clip).
Sources: YouTube: 9news Channel