There are two problems with gathering data: Not taking action on the data or the data being innacurate.
We stockpile information in our heads, journals, and databases. We do this to potentially utilize the data in the future for the benefit of ourselves, our organizations, or for somebody else. If we never do anything with the information we’ve gathered, we have wasted time and brain space when we gathered it in the first place.
Even worse than not using data, is using data that is inaccurate. Was your perception of an individual skewed by your own sour mood? Have you ever spent time persuading an individual who had no authority to make a decision because your information said he was the decision maker?
One Moore Thing: First decide whether or not to save a particular piece of information, then make sure the data is correct so you can maximize it’s value.