Illusion of external agency
The illusion of external agency is believing that a preference or good feeling you created yourself was caused by some wise outside force, such as fate, an expert or a guide. People underestimate how much their own minds adjust to make the best of a situation.
In everyday life
After an assigned roommate becomes a close friend, a student credits the housing office with a brilliant match, when she has simply grown to like the person she lives with.
You grow to love the car a salesperson steered you toward and credit his amazing insight into your needs, though you would probably have grown just as fond of the other model.
Why your mind does this
Social life depends on guessing what others think and feel. Using our own mind as a model for other minds is fast and often roughly right, because people share a lot. It let our ancestors predict friends and rivals without needing to ask.
Its family, in 30 seconds: Mind reading
How to spot it
Ask whether the outside source really knew what was best, or whether you adapted and came to like the result.
How to counter it
Remember that you tend to grow content with most reasonable outcomes, and give yourself some of the credit.
Same family: Mind reading
SourceGilbert et al. (2000)