People get angry and act like a jerk and think that “I was having a bad day” is a good excuse because they aren’t usually like that. If famous, they may give a public apology saying that’s “not who I am” (I think because on most days of their life they didn’t do anything like that).
Who you are near your worst is actually really important and says a lot about you. For many purposes, judging people by the minimum quality standard they maintain at all times is a better approach than looking at their peaks.
Very exceptional circumstances can be discounted like if you said or did something bad while you were having a stroke or after someone drugged your drink without your knowledge. But if your dog died, or your colleague said something nasty to you, or you slept poorly, or you voluntarily got drunk or high, those are not good excuses; that’s just part of life.
It’s OK to have some particularly bad days, but you still shouldn’t yell at your family, customer service workers, or people on Twitter. Instead, you should recognize you’re having a bad day and deal with it appropriately: take your time more, be slower to speak, don’t make any big decisions with lasting consequences, avoid risk, maybe take a nap, etc. And this should be infrequent. Like if less than once a month you spend a day or less being careful and not doing much, and you’re successful at managing it, that’s OK. If once a month you’re a jerk to people, then you’re a jerk. And if once a week or more often you have a really bad day, that isn’t a special outlier; it’s part of your regular life.
@lmd @Dface for context also see Dface's Topic about Self-Help Books He's Reading - #55 by Elliot