A: Mary told me you stopped smoking at home.

B: Yeah. I was smoking on my patio one day last month and I carelessly left a cigarette burning on the ground. I nearly set my house on fire because of that! This was the wake-up call.

Note: Literally, this term refers to a phone call that one schedules to be placed to one’s hotel room in order to be woken up at a certain time. As a metaphor it refers to something which shocks people, making them understand how serious a problem is and causing them to take action to solve that problem. For example: The recent storms and floods have been a wake-up call for many people about the reality of climate change.