Motivated reasoning as a faulty way to think.

… People do not seem to be at liberty to conclude whatever they want to conclude merely because they want to. Rather, I propose that people motivated to arrive at a particular conclusion attempt to be rational and to construct a justification of their desired conclusion that would persuade a dispassionate observer. They draw the desired conclusion only if they can muster up the evidence necessary to support it (cf. Darley & Gross, 1983). In other words, they maintain an “illusion of objectivity” (Pyszczynski & Greenberg, 1987; cf. Kruglanski, 1980). To this end, they search memory for those beliefs and rules that could support their desired conclusion. They may also creatively combine accessed knowledge to construct new beliefs that could logically support the desired conclusion. It is this process of memory search and belief construction that is biased by directional goals (cf. Greenwald, 1980). The objectivity of this justification construction process is illusory because people do not realize that the process is biased by their goals, that they are accessing only a subset of their relevant knowledge, that they would probably access different beliefs and rules in the presence of different directional goals, and that they might even be capable of justifying opposite conclusions on different occasions.
For example, people who want to believe that they will be academically successful may recall more of their past academic successes than of their failures. They may also use their world knowledge to construct new theories about how their particular personality traits may predispose them to academic success (Kunda, 1987). If they succeed in accessing and constructing appropriate beliefs, they may feel justified in concluding that they will be academically successful, not realizing that they also possess knowledge that could be used to support the opposite conclusion. The biasing role of goals is thus constrained by one’s ability to construct a justification for the desired conclusion: People will come to believe what they want to believe only to the extent that reason permits. Often they will be forced to acknowledge and accept undesirable conclusions, as they appear to when confronted with strong arguments for undesired or counterattitudinal positions (Petty & Cacioppo, 1986)…