for example?
Phishing e-mails originate from questionable accounts that sound legitimate, have generic greetings and/or signatures, and often contain grammar or spelling errors that give them away.
There is a picture of an example phishing mail on this site where they mention that a wrong date format was used. You could say they just did a mistake but I believe they know what they're doing. They don't want to target people who would spot such mistakes. They want to reach the people who wouldn't.
And when in doubt: it's better to overestimate people than to underestimate them - especially when it comes to picking your battles :)
so it's purposely making mistakes to filter targets, good point!
it's better to overestimate people than to underestimate them - especially before you pick a fight :)
much wisdom from @ekzyis