The polar opposite

As I related yesterday, I took my van to my mechanic. He tuned it up and it's running great. Yet there's still something wrong.
Driving home, I couldn't shake the feeling that it wasn't quite right. It drove smoothly and accelerated well. It did better than it's done in a long time in fact. I couldn't quite put my finger on the problem though.
That's when I noticed this blank spot on the dashboard. That blank spot didn't look right at all. I wondered what it could be. I began to worry about what it could be.
Then I realized that my service engine soon light was not on. My mechanic had tuned up the van, and that apparently caused the warning light to stay off. So today, right after stating that I did not worry about idiot lights begin on, I'm concerned about the fact that one particular idiot light, one that I'm very used to being on, is off.
It'll be weeks now before I'm really comfortable driving the thing. Maybe I should have left well enough alone.