🙅♀️ Cognitive Dissonance:
Mental discomfort from holding conflicting beliefs.
This internal contradiction includes the mental conflict when your beliefs don't reflect your actions.
For example; craving fast food, but also wanting to feel healthy, or have the perception that you're someone who cares about fitness.
Often people will address this by:
Lying to themselves (i.e., opting to believe a lie, or excusing an action as "not that contradictory").
Changing their behaviour (i.e., an animal-lover deciding to not eat meat).
Adopting a new behaviour (i.e., going for a run to offset eating a cake).

✅ Churn
If the discomfort of holding conflicting opinions is too great, the user may decide to not use your product at all.
✅ Feature usage
Instead of churning, people may simply avoid certain features.
For example, the user may avoid purchasing your 'chocolate-to-your-door' subscription, even if they eat the same amount daily. It's not because they wouldn't benefit from the service, it's because that specific feature (i.e., commitment) may trigger their cognitive dissonance.
✅ Habits
The user may have a natural tendency to avoid habits that they feel conflict with their opinion of themselves (i.e., avoid being addicted to Netflix).
✅ Input quality
The user may lie (or exaggerate) how much they do certain things, increasing the difficulty of user testing.
i.e., "how much do you expect to use the gym?" is unlikely to reflect their actual usage, and may even create cognitive dissonance if you remind them of this commitment later.
✅ Discomfort & frustration
Cognitive dissonance is both frustrating and uncomfortable.
✅ Happiness & enjoyment
By removing (or reducing the effects of) cognitive dissonance, you can find that your product is more enjoyable to use.
Here's how you could design a product, with these responses in mind:
Reaction #1: Lying to themselves
Imagine that you're running Netflix, and you're worried that although users want to binge watch trash TV, they perceive themselves as smart individuals who seek to constantly learn more about the world.
You might decide to never remind them how long they've been watching particular shows.
i.e., "you've watched Love Island for 412 hours this year" might actually create churn, as people feel guilty.
(Note: this is often used as a dark pattern, like how casinos hide clocks so you don't know how long you've been gambling).
Reaction #2: Changing their behaviour
You're in charge of sales at Beyond Meat (a meat-alternative company), and you're trying to capture new customers through your website.
You might encourage people to adopt a new habit of being vegetarian, rather than buying Beyond Meat as a one-off.
For example, you could send the user a "days since I last ate meat" calendar, for them to tick off.
Reaction #3: Adopting a new behaviour
You're running Strava (a fitness tracking app), and you're trying to reduce churn.
People are signing up, going for a few runs, but then leaving. Although they want to be someone who's jogging every morning, they can't be bothered.
You could experiment with rewarding users post-run, with an opposing behaviour. For example, giving them a "1 free McDonalds pass", to alleviate the guilt.
Instead of fighting the user's instinctive behaviour (to stop running), you'd be implementing a counterbalanced habit (to use Strava).