A woman whose father shot five people in the U.S. state of Georgia a few days ago has been quoted as saying she knew ol' pop was dangerous. He was, she said, "a ticking time bomb."
This phrase "ticking time bomb," which is uttered/written probably hundreds of times a day on TV, Facebook, and many other public media, is one that really grates on my much-assaulted grammatical psyche.
It's not just trite, it's redundant. If you have a time bomb, it's ticking. So "time bomb" seems enough. "Ticking bomb" seems fine. But not both, please.
Unless of course, you mean to emphasize that someone has actually built a bomb that utilizes an analog clock rather than a digital device. I'll bet that situation is a rare one in this day and age; to ridicule such a benighted bomb-builder would be entirely justified. So then it's OK.