A dentist and a car guy

Brian's never been much of a "car guy," but today, he impressed me. Okay, so it was just changing out the battery in the Rover, but still, I was pleasantly surprised.
So here's the story: Last night, we get in the car to head out to dinner, and B turns the key. "Click, click, click." Now me, I know what a dead battery sounds like. Brian's never had to bother though, and I know that probably, if we just jump it, the battery will be fine. Anyway, I was too hungry to deal with it at that point, so we went to dinner in the Jimmy, then came home and, just to be sure that was the problem, jumped the Rover. (Don't be surprised that once again, my roadside assistance arsenal came in handy. OF COURSE I have jumper cables in the back of my car!) The car started up just fine, and Brian decided he would head to an auto parts shop for a new battery this morning.
After the required starts and stops since neither one of us is a mechanic, we got down and dirty under the "bonnet" of the car, and B traded out the bad, crappy battery for the new one he bought. Yay! (Seeing him with his dirty hands and a bit sweaty from the effort made me kinda hot for him. I told him so.) So now, all is fine.
But tell me, can anything else go wrong with this car? I hate to ask and thereby jinx it, but jeez.