Source: http://m.psychologytoday.com/blog/in-practice/201301/50-common-cognitive-distortions

1. Personalizing.

Taking something personally that may not be personal. Seeing events as consequences of your actions when there are other possibilities. For example, believing someone’s brusque tone must be because they’re irritated with you. (Tips for not personalizing.)

2. Mindreading. Guessing what someone else is thinking, when they may not be thinking that.

3. Negative predictions.

Overestimating the likelihood that an action will have a negative outcome.

4. Underestimating coping ability.

Underestimating your ability cope with negative events.

5. Catastrophizing.

Thinking of unpleasant events as catastrophes.

6. Biased attention toward signs of social rejection, and lack of attention to signs of social acceptance.

For example, during social interactions, paying attention to someone yawning but not paying the same degree of attention to other cues that suggest they are interested in what you’re saying (such as them leaning in).

7. Negatively biased recall of social encounters.

Remembering negatives from a social situation and not remembering positives. For example, remembering losing your place for a few seconds while giving a talk but not remembering the huge clap you got at the end.

8. Thinking an absence of effusiveness means something is wrong.

Believing an absence of a smiley-face in an email means someone is mad at you. Or, interpreting “You did a good job” as negative if you were expecting “You did a great job.”

9. Unrelenting standards.

The belief that achieving unrelentingly high standards is necessary to avoid a catastrophe. For example, the belief that making any mistakes will lead to your colleagues thinking you're useless.

10. Entitlement beliefs.

Believing the same rules that apply to others should not apply to you. For example, believing you shouldn’t need to do an internship even if that is the normal path to employment in your industry.

11. Justification and moral licensing.

For example, I’ve made progress toward my goal and therefore it’s ok if I act in a way that is inconsistent with it.

12. Belief in a just world.

For example, believing that poor people must deserve to be poor.

13. Seeing a situation only from your own perspective.

For example, failing to look at a topic of relationship tension from your partner’s perspective.

14. Belief that self-criticism is an effective way to motivate yourself toward better future behavior.

It’s not.

15. Recognizing feelings as causes of behavior, but not equally attending to how behavior influences thoughts and feelings.

For example, you think “When I have more energy, I’ll exercise” but not “Exercising will give me more energy.”

16. All or nothing thinking.

 e.g., "If I don’t always get As, I’m a complete failure."

17. Shoulds and musts.

For example, "I should always give 100%." Sometimes there are no important benefits of doing a task beyond a basic acceptable level.

18. Using feelings as the basis of a judgment, when the objective evidence does not support your feelings.

e.g., "I don’t feel clean, even though I’ve washed my hands three times. Therefore I should wash my again." (Obsessive Compulsive Disorder example).

19. Basing future decisions on “sunk costs.”

e.g., investing more money in a business that is losing money because you’ve invested so much already.

20. Delusions.

Holding a fixed, false belief despite overwhelming evidence to the contrary. For example, believing global warming doesn’t exist. Or, believing you’re overweight when you’re 85lbs.

21. Assuming your current feelings will stay the same in the future.

For example, “I feel unable to cope today, and therefore I will feel unable to cope tomorrow.”

22. Cognitive labeling.

For example, mentally labeling your sister’s boyfriend as a “loser” and not being open to subsequent evidence suggesting he isn’t a loser.

23. The Halo Effect.

For example, perceiving high calories foods as lower in calories if they’re accompanied by a salad.

24. Minimizing.

e.g., “Yes I won an important award but that still doesn’t really mean I’m accomplished in my field.”

25. Magnifying (Cognitively Exaggerating).

For example, blowing your own mistakes and flaws out of proportion and perceiving them as more significant than they are.

Making a mountain out of a molehill, but not quite to the same extent as catastrophizing.

26. Cognitive conformity.

Seeing things the way people around you view them. Research has shown that this often happens at an unconscious level. See the Asch experiment. (video)

27. Overgeneralizing

Generalizing a belief that may have validity in some situations (such as “If you want something done well, you should do it yourself.”) to every situation. This is a type of lack of psychological flexibility.

28. Blaming others.

29. Falling victim to the “Foot in the Door” technique.

When someone makes a small request to get a “Yes” answer, then follows up with a bigger request, people are more likely to agree to the big request than if only that request had been made.

30. Falling victim to the “Door in the Face” technique.

When someone makes an outlandish request first, then makes a smaller request, the initial outlandish request makes the smaller request seem more reasonable.

31. Focusing on the amount saved rather than the amount spent.

e.g, Focusing on the amount of a discount rather than on whether you’d buy the item that day at the sale price if it wasn’t listed as on sale.

32. Overvaluing things because they're your's.

e.g., perceiving your baby as more attractive or smart than they really are because they're your's.

Or, overestimating the value of your home when you put it on the market for sale because you overestimate the added value of renovations you've made.

33. Failure to consider alternative explanations.

Coming up with one explanation for why something has happened/happens and failing to consider alternative, more likely explanations.

34. The Self-Serving Bias

34. The Self-Serving Bias The self-serving bias is people's tendency to attribute positive events to their own character but attribute negative events to external factors. (Tips for overcoming the self-serving bias.)

35. Attributing strangers' behavior to their character and not considering situational/contextual factors.

36. Failure to consider opportunity cost.

For example, spending an hour doing a low ROI task and thinking "it's only an hour" and not considering the lost potential of spending that hour doing a high ROI task.

37. Assumed similarity.

The tendency to assume other people hold similar attitudes to your own.

38. In-group bias.

The tendency to trust and value people who are like you, or who are in your circle, more than people from different backgrounds.

39. "You don't know what you don't know."

Getting external feedback can help you become aware of things you didn't even know that you didn't know! 

40. The tendency to underestimate how long tasks will take.

41. The belief that worry and overthinking will lead to problem solving insights.

In fact, overthinking tends to impair problem solving ability and leads to avoidance coping.

42. Biased implicit attitudes.

Psychologists use a test called the implicit association test to measure attitudes that people subconsciously hold. Results show people subconsciously associate fat with lazy etc. 

It's useful to be mindful that you may subsciously hold biased attitudes, then you can consciously correct for them.

43. The Peak-End Rule.

The tendency to most strongly remember (1) how you felt at the end of an experience, and (2) how you felt at the moment of peak emotional intensity during the experience. Biased memories can lead to biased future decision making.

44. The tendency to prefer familiar things.

Familiarity breeds liking, which is part of why people are brand loyal and may pay inflated prices for familiar brands vs. switching.

45. The belief you can multi-task.

When you're multi-tasking you're actually task (and attention) shifting. Trying to focus on more than one goal at a time is self-sabotage.

46. Failure to recognize the cognitive benefits of restorative activitIes and activities that increase positive emotions.

For example, seeing humor or breaks as a waste of time.

47. Positively biased predictions.

For example, expecting that if you sign up to a one year gym membership you will go, if this hasn't been the case in the past.

48. Cheating on your goals based on positive behaviors you plan to do later.

For example, overeating today if you expect you'll be starting a diet next week. Often the planned positive behaviors don't happen. 

49. Repeating the same behavior and expecting different results (or thinking that doubling-down on a failed strategy will start to produce positive results). 

For example, expecting that if you nag more, your partner will change. 

50. "I can't change my behavior." (or "I can't change my thinking style."

Instead of telling yourself "I can't," try asking yourself how you could shift your behavior (or thinking style) by 5%.

How to Become Mindful of Your Cognitive Distortions?

Try printing this article and highlighting the cognitive distortions you think apply to you. I suggest you then pick one cognitive distortion at a time and keep a running list for a week of how that cognitive distortion manifests in your life.