that I had let myself be happier." Determinants of intensity Action versus inaction There is an interplay between action versus inaction and time. Regrets of an action are more intense in the short term, whereas regrets of inaction are more intense over the long term. Age In a 2001 study, high intensity of regret and intrusive thoughts in older adults was related to self-control, and low internal control was expected to be self-protective and help to decrease regret. In younger adults, internal-control facilitated active change and was associated with low intensity of regret. Opportunity People's biggest regrets occur where they perceive the greatest and most important opportunity for corrective action. When no opportunity exists to improve conditions, thought processes mitigate the cognitive dissonance caused by regret, e.g. by rationalization, and reconstrual. Regret pushes people toward revised decision making and corrective action as part of learning that may bring improvement in life circumstances. A 1999 study measured regret in accordance to negative reviews with service providers. Regret was an accurate predictor of who switched providers. As more intense regret is experienced, the likelihood of initiating change is increased. Consequently, the more opportunity of corrective action available, the larger the regret felt and the more likely corrective action is achieved. Feeling regret spurs future action to make sure other opportunities are taken so that regret will not be experienced again. People learn from their mistakes. Lost opportunity principle With a lost opportunity regret should intensify, not diminish, when people feel that they could have made better choices in the past but now perceive limited opportunities to take corrective action in the future. "People who habitually consider future consequences (and how they may avoid future negative outcomes) experience less, rather than more, intense regret after a negative outcome." This principle offers another reason as to why education is the most regretted aspect in life. Education becomes a more limited opportunity as time passes. Aspects such as making friends, becoming more spiritual, and community involvement tend to be less regrettable which makes sense because these are also aspects in life that do not become limited opportunities. As the opportunity to remedy a situation passes, feelings of hopelessness may increase. An explanation of the lost opportunity principle can be seen as a lack of closure: Low closure makes past occurrences feel unresolved. Low closure is associated with "reductions in self-esteem and persistent negative affect over