You had one beer.

I met you at the bar for some loud blues music and a drink, but it got late and I wanted to hit the hay. I hate driving, and you knew how to drive stick, so when we left the bar I asked you to take the wheel for the ride home. I handed you the keys and slid into the passenger seat, only after you swore you only had one drink. I must be a pretty trusting person, because I believed you, even after you were exchanging information with the guy whose parked car you hit.

Maybe you should have mentioned the half dozen benzodiazepines you took before I got there.