Fallacies can be used...
accidentally - during persuasion ,
intentionally - as part of a systematic plan to violate your personhood (fool you),
or by sociopaths - just because they're not asleep.
Spotting if people use fallacies can be a good way to assess their character.
You can also find them in newspaper articles, news shows, and speeches.
There use is discouraged in scientific papers and legitimate web sites
but can be entertaining in the hands of a good comedian.

This is an example of an informal fallacy

Interesting stuff to know if you don't want to be a fool.

Sometimes logic is illogical

If you can understand this, then you are smart.

Learn a fallacy a day... keep the BS away.