The worst I ever had was coming back to London from LA on Virgin's A400-600 a couple of years ago. I knew it was going to be bad when the captain said "the good news is that our flying time is just 9hrs today, the bad news is that that means high turbulent winds". It turned out be like the OP described and people were crying. A gentleman in the middle row next to me was screaming out "oh my god, we're gonna die!" constantly, which didn't help
Even though I know how tough they're built, it wasn't very enjoyable experience and I was scared. Somehow when you're driving yourself it feels less bad even when it's bad.