A circle riddle is:
     
Q: What did the triangle say to the circle?
A: You’re pointless!
   
The riddle has been cited in print since at least 2005.
   
“Why was the circle depressed?”/“She thought her life was pointless” is a similar riddle.
     
     
Google Books
Lunch Money
By Andrew Clements
New York, NY: Aladdin Paperbacks (Simon & Schuster)
2007 (2005)
Pg. 61:
What did the triangle say to the circle? Your life seems so pointless.
 
Newspapers.com
2 October 2011, Los Angeles (CA) Times, “The Kids’ Reading Room: Jokes & Riddles,” pg. H4, col. 3:
What did the triangle say to the circle? Your life seems so pointless.
Carina, 11
Oxford Academy
Cypress
 
Google Books
Bouncy Ben’s Brain Busters:
An A-Z of Activities with Hours of Fun for Everyone!
By Sarah Edwards
Surrey, UK: Letterland International Ltd
2012
Pg. 27:
What did the triangle say to the circle? You’re so pointless!
     
Google Books
Humour and Jokes
By Arijit Ghosh
Smashword
2015
Pg. ?:
Q: What did the triangle say to the circle? A: You’re pointless!
   
Reddit—3amjokes
Posted by u/invisiblebecause September 16, 2015
What did the triangle say to the circle?
You’re pointless!
   
Reddit—Jokes
Posted by u/Faldrilan October 15, 2018
What did the Triangle say to the Circle?
You’re pointless.
COMMENTS
DaShMa_
There’s three sides to every story..
glesgakis
Let’s look at this from another angle
 
Twitter
PushpinASH⁷ is renovating 🛠
@ddaengkillua
What did the triangle say to the circle?  You’re pointless!
6:36 PM · Nov 23, 2018·Twitter for iPhone
 
Twitter
Lixie Wants To Play
@dumbdumblixie
Daily jokes with ya boiー
What did the triangle shape say to the circle shape?
You’re so pointless
11:04 PM · Jul 9, 2020·Twitter for Android