What is the most important upgrade to TV since the 1950s?

No, it's not color TV, LCD, HD, surround sound, cable or satellite. It's the remote's 'mute button.' With it, I can ignore all of the medical ads about every illness imaginable or every orifice. Do advertisers really think their money is well spent placing TV ads in the middle of the news? Between the mute button and the video recorder, I don't know one product from another and I plan on keeping it that way!