Television is one of the greatest life-wasters of the modern age. And, of course, the Internet is running to catch up, and may have caught up. You can be more selective on the Internet, but you can also select worse things with only the Judge of the universe watching. TV still reigns as the great life-waster. The main problem is not how much smut is available, though that is a problem. Just the ads are enough to sow fertile seeds of greed and lust, no matter what program you’re watching. The greater problem is banality. A mind fed daily on TV diminishes. Your mind was made to know and love God. Its facility for this great calling is ruined by excessive TV. The content is so trivial and so shallow that the capacity of the mind to think worthy thoughts withers, and the capacity of the heart to feel deep emotions shrivels.
(John Piper, Don’t Waste Your Life, p.120)
This is a toughy! But I can’t but agree.