When I wrote some time ago about a confusing car jumpstarting episode, my main confusion was that my battery terminal in my Ion under the hood didn't have two places to attach the cables (positive and negative, of course). I ended up using the actual battery in the trunk under the floor to start a stranded woman's car. My owner's manual showed a battery terminal with two posts and I was perplexed.
So recently I get a battery jumpstarter, to prepare for a winter, and the short manual explains all--most cars nowadays have but one post and I should have grounded the other cable on the frame of my car.
Well, of course, now that I think about it. It was obvious once I read that.
I suppose if I was a real he-man I'd have figured that out at the time. But in my defense, my manual clearly stated I had to connect both cables to battery posts. Which I could only do at the actual battery.
Oh well, I learned something and didn't do any damage in the process. That's good, eh?