When you make a mistake while trying to correct another person’s mistake?
And I’m sure this has been answered before, but I’m too lazy to search.
Karma.
If you’re referring to editing or proofreading, generally people call it Muphry’s Law although this board prefer’s Gaudere’s Law after a moderator who called attention to the phenomenon back in the day.
Muphry’s Law, eh? Sounds about right. 
Gaudere’s Law!! That’s what I was trying to think of. Thanks. Unfortunately, since it’s exclusive to this board, the person I wanted to use it on won’t know what I’m talking about.
It’s not exclusive to this board any more, I don’t think.
Per Wikipedia, that term (with that deliberate misspelling) is more than two decades old.
To clarify: Murphy’s Law and Gaudere’s Law are not synonymous:
Murphy’s Law is: “If anything can go wrong, it will.”
Gaudere’s Law is “making an error when calling atention to someone else’s error.”
No one mentioned Murphy’s Law so I’m not sure why you think it needs clarification.
In German, there is a word that means “making things worse when trying to make them better”: verschlimmbessern.
I wonder what the Law is for when you erroneously comment about another Law…
(To be clear to panache45, Muphry’s Law is a different law than Murphy’s Law, not a poster’s accidental typo.)
Please use descriptive thread titles. Title edited to indicate subject.
Colibri
General Questions Moderator
I think that, in “correcting” Inner Stickler, panache45 actually illustrates Muphry’s Law. 
He was “correcting” a spelling error, right?
Finally - the thread became self referential. That took ages.
Sounds like today’s xkcd.
On behalf of all people, everywhere, I would like to thank the Germans for giving us this beautiful word that would so accurately describe what my boss does, if there were anything to “bessern” in my work in the first place.
I hope everyone enjoyed the ratio of vowels:consonants? For full appreciation, pay attention to the “rschl” part. Though not unusual in German, it is always a fun sight.
So thanks German language! You always know just how I feel.
For the win!
Actually, when I read the topic, the word that came to my mind was “ironic”.
If you search for “Gaudere’s Law” on Wikipedia, it redirects to “Muphry’s Law.”
How about “Murphy’s Law”?