Cognitive therapy and its variants traditionally identify ten cognitive distortions that maintain negative thinking and help to maintain negative emotions.  Eliminating these distortions and negative thought is said to improve mood and discourage maladies such as depression and chronic anxiety. The process of learning to refute these distortions is called "cognitive restructuring".
All-or-nothing thinking - Thinking of things in absolute terms, like "always", "every" or "never". Few aspects of human behavior are so absolute. (See false dilemma.)
Overgeneralization - Taking isolated cases and using them to make wide generalizations. (See hasty generalization.)
Mental filter - Focusing exclusively on certain, usually negative or upsetting, aspects of something while ignoring the rest, like a tiny imperfection in a piece of clothing. (See misleading vividness.)
Disqualifying the positive - Continually "shooting down" positive experiences for arbitrary, ad hoc reasons. (See special pleading.)
Jumping to conclusions - Assuming something negative where there is no evidence to support it. Two specific subtypes are also identified:
Mind reading - Assuming the intentions of others.
Fortune telling - Predicting how things will turn before they happen. (See slippery slope.)
Magnification and Minimization - Inappropriately understating or exaggerating the way people or situations truly are. Often the positive characteristics of other people are exaggerated and negative characteristics are understated. There is one subtype of magnification:
Catastrophizing - Focusing on the worst possible outcome, however unlikely, or thinking that a situation is unbearable or impossible when it is really just uncomfortable.
Emotional reasoning - Making decisions and arguments based on how you feel rather than objective reality. (See appeal to consequences.)
Making should statements - Concentrating on what you think "should" or ought to be rather than the actual situation you are faced with, or having rigid rules which you think should always apply no matter what the circumstances are. Albert Ellis' termed this "Musterbation". (See wishful thinking.)
Labeling - Explaining behaviors or events, merely by naming them; related to overgeneralization. Rather than describing the specific behavior, you assign a label to someone or yourself that puts them in absolute and unalterable terms.
Personalization (or attribution) - Assuming you or others directly caused things when that may not have been the case. (See illusion of control.) When applied to others this is an example of blame.