We aren't acting as adults: we can't look at something shiny and say, "I want it, but it would be bad for me, so I'll leave it alone." At least some of the dangers of these things are obvious: unnatural levels and kinds of sharing, contrived, manipulative reactions, vast potential for privacy violation and misuse of data, and tons of time lost without compensation of any kind. Why don't we all refuse?
I didn't, and I should have. I've recently dropped Facebook entirely and am paring back my reliance on Google. Looking through my Facebook data download, I'm shocked at my foolishness, especially in the first couple years: I was old enough to know better! I hope I've learned my lesson, and that others do too, before we seriously mess up our society --- if we haven't already.