Whatever you do, forget your petty reasons.
For let’s say you come up with ten reasons to guide or explain an action. You can then order these reasons by their causal or explanatory power, with the first being your strongest reason, followed by your secondary reason, and so on. Ordered that way, chances are that your primary reason is socially acceptable and morally respectable, rather than selfish and reprehensible.
Now ask yourself: Is this because your individual will is so closely in line with society’s collective will and because you’re such a good person? Or could it be that reasons fundamentally are something you concoct in order to better communicate your social and moral worth?
After all, the way you acquired—as a child—the very concept of reason was when adults commanded you to “explain yourself!” Which, of course, is a trigger to hide the truth and say something acceptable.1
So if you value self-knowledge over self-flattering stories, forget the reasons for your actions. A cool mind is unburdened, unbiased by the dross of reasons, which mainly are products of rationalization, not of rationality.
Finally, what about other people’s reasons for their actions? Here, instead of cynically searching for ulterior motives (“He’s only doing that because…”), it is more worthwhile to look at the consequences and ask, “Are they good?”