One of my colleagues had given his car for repair after it had stalled all of a sudden.

The mechanic reported that the radiator was punctured and since he had driven his car for sometime after this happened, the engine became too hot. Even the spark plugs were fused into the engine due to the heat. They mentioned that the engine might need to be replaced.
<$500 to replace the radiator
$6000 to replace the engine

If he had glanced at the temperature gauge on the car and stopped the car when it was too hot, he could have saved the engine.

I never have the habit of looking at the temperature gauge. So this is an important lesson – make sure to glance at your temperature gauge once in a while.