“I’ve mixed I Can’t Believe It’s Not Butter with butter & now I don’t know what to believe!”

“I Can’t Believe It’s Not Butter!” is a substitute product for butter. “RT: @haydenblack: I put butter in my I Can’t Believe It’s Not Butter. Now I don’t know what to believe” was posted on Twitter by Carlton Hackett on January 6, 2010. (The original tweet is not available.)
     
“I accidentally mixed the I Can’t Believe It’s Not Butter in with the regular butter and NOW I DON’T KNOW WHAT TO BELIEVE!” was posted on Twitter by Matthew on March 23, 2011. “I’ve just mixed ‘I can’t believe it’s not butter’ with butter and now I don’t know what to believe!” was posted on Twitter by The Dad Joke Man on September 19, 2020.
   
“A tub of margarine fell on my foot 3 weeks ago and it still hurts. I can’t believe it’s not better” and “Sneezed all over my toast. Can’t believe it snot butter” are other jokes on the product name.
     
     
Wikipedia: I Can’t Believe It’s Not Butter!
I Can’t Believe It’s Not Butter! is a spread brand produced by Upfield and marketed as a substitute for butter.
     
Twitter
Carlton Hackett
@Bluraven
RT: @haydenblack: I put butter in my I Can’t Believe It’s Not Butter. Now I don’t know what to believe.
2:45 PM · Jan 6, 2010·Twitter Web Client
   
Twitter
Stephanie Thorpe
@TheStephThorpe
haha! RT @haydenblack: I put butter in my I Can’t Believe It’s Not Butter. Now I don’t know what to believe.
3:26 PM · Jan 6, 2010·Twitter Web Client
   
Twitter
Matthew
@sucittaM
I accidentally mixed the I Can’t Believe It’s Not Butter in with the regular butter and NOW I DON’T KNOW WHAT TO BELIEVE!
3:13 PM · Mar 23, 2011·Echofon
     
Twitter   
Bob Kostic
@causticbob
I accidentally mixed my ‘I can’t believe it’s not butter’ with my real butter.
Now I don’t know what to believe.
7:08 PM · Dec 10, 2012·TweetDeck
 
Twitter
The Weed Yorker
@weedyorker
Accidentally mixed my I can’t believe it’s not butter with my real butter. Now I don’t know what to believe….
7:22 PM · Jan 8, 2014·Twitter Web Client
 
Twitter
Anthea
@Anthea06274890
“I mixed “I can’t believe it’s not butter”....with regular butter…And now I don’t know what to believe…” —AOC
8:59 PM · Jun 25, 2020·Twitter for iPhone
 
Twitter
The Dad Joke Man
@DadJokeMan
I’ve just mixed ‘I can’t believe it’s not butter’ with butter and now I don’t know what to believe!
5:33 AM · Sep 19, 2020·Twitter for iPhone