Impact bias
Impact bias is overestimating how strongly and how long future events will affect your feelings. People adapt to both good and bad news faster than they expect.
In everyday life
A student believes being rejected by their first-choice college will make them miserable for years, yet feels fine within a few months.
You are sure that moving into a house with a pool will make you happy every single day for years, yet by the second summer it feels like just another part of the house.
Why your mind does this
Imagining the past and the future is hard, so the brain uses the present as a template. Assuming things will stay roughly as they are now is a quick and usually workable guide. Making sense of events after the fact also helps us learn lessons and feel in control.
Its family, in 30 seconds: Projecting ourselves
How to spot it
Ask how you actually felt a few months after a similar big event in your past.
How to counter it
Remember that feelings usually drift back toward your normal level, and think about the everyday parts of life that will stay the same.
Same family: Projecting ourselves
SourcesGilbert et al. (1998)·Wikipedia