A check

You have just read something that answered the doubt well, and you feel much better. On this lesson, what is the most useful thing to notice about that feeling?

That the argument must have been a strong oneThat you should save it somewhere so you can read it again next timeHow long the relief lasts, because that is the thing that tells you which of the two you haveThat your faith has been restored and the matter is closed
Yes

The first two treat the relief as the result. But relief is what an anxiety symptom is seeking, which is precisely why it is short, and a saved folder of answers is usually a record of how many times the same relief has been bought. The fourth is a verdict, and verdicts about your own inner state are the thing that cannot be obtained. The duration is the useful information, and it is the one thing here you can actually observe.