How X’s (formerly Twitter) mistake taught me two important UX principles
Late last year Twitter released an update for their mobile application. It was a change in user flow for retweeting and quoting a tweet. Now I know many of you might not know how Twitter works but don’t worry, I will explain it to you. If you are familiar you can skip the next part.
Article for the news about the update: https://slate.com/technology/2020/10/twitter-retweet-change-election.html
How Twitter works
To start, with you need to know these 3 things:
Tweet: When you post a thought, an idea, or a simple statement about anything or everything it is called a tweet.
Retweet: When you agree with a tweet made by someone else and want to share it with the people that follow you, you can retweet it, it's just like echoing a statement.
Quote Tweet: Now when you see a tweet and you think you have something to add to the conversation(let it be in agreement or disagreement) but also at the same time want to hear opinions from your followers as well, you can quote the tweet.

Change in user flow
This is the old user flow in which, once the user clicks the icon to retweet, the user was presented with an overlay screen with the option to quote it or to retweet it.

This is the new user flow in which, once the user clicks the icon to retweet, the user is taken to the quoting screen. Now if the user adds any comment, it would be a quoted tweet, and if he tweets it blank it would be a retweet.

Intention/Reason for change
Just an FYI here, I am not a Twitter employee, so I could only assume and predict with the knowledge I have about UX
The intention, I believe, the change was made was to reduce the number of clicks a user makes while retweeting and quoting tweets and the time it takes to do so.
The other reason, I believe is, they targeted the user base that was already familiar with quoting and retweeting and betted on them to understand the change and use it, as it would make things easier for them.
But… users hated it
The moment it was launched everyone started tweeting about how they hate the new way to retweet things. The users were confused, they quoted tweets which they wanted to retweet.
It was so confusing for some that they even started to avoid retweeting things, even Twitter’s official account kind of acknowledged it.

Here is a link to see all the hundreds of thousands of tweets about how much users hate the new method — Twitter Search
What went wrong and why
When I first saw the hate ( if I am being honest even I hated it) I really wondered why are users hating the update. So I did some digging and after a while, I remembered these 2 UX Principles that I had read in books and articles. The first being …
1. Krug’s second law of usability
In his book Don’t Make Me Think, author Steve Krug explains the second law of usability which is:
“It doesn’t matter how many times users have to click, as long as each click is a mindless, unambiguous choice.”
That means users don’t mind clicking on the retweet and quote tweet button on the overlay screen of the old user flow as long as it isn't confusing them.

2. Jakob Nielsen’s concept of Mental Model
Now I was aware of the concept of the mental model but I didn’t relate the Twitter situation with it directly, but after some research and going through Jakob Nielsen’s Article in NNgroup , I saw the relation.
“A mental model is a model of what users know or they think they know about a system.”
After using Twitter for years or months most users have the way retweet works entrenched into their brains and they have created their own mental model on how it should work, but when Twitter changes it, their mental model is challenged which results in bad User Experience.
What happened next
Well, we all make mistakes and have seen failure even after having good intentions in our minds. But we need to learn from it to survive, to be at the top, and to stay there, which Twitter has been for a while.
They changed it back to the previous model.

They say examples help you learn things faster and well I have come to believe it as I am never forgetting these 2 UX principles.
I hope this was worth your time and helped you learn something.