To each their own, but I have never left a restaurant without leaving a tip, ever. No matter how bad something was, I never felt like it was the server's fault I guess, at least not enough to do that to somebody anyway.
I'm with ya on the "those things should stay private" but as chicolby already mentioned, younger folks now-a-days think nothing of telling the whole world about their life through social media. My 16 y/o daughter goes to school with a friend she grew up with in our neighborhood, she's a cute girl that doesn't need to slut it up so much for attention, but nonetheless, she thinks nothing of send the most nasty and vile texts showing all over her body sans clothes. Bragging about who she's been with. Freaking 16, and tells the whole world about her sex life and there are literally hundreds of naked pics of her floating around school, and she isn't the only one. Just a different age now I guess.