Final answer:
Derrick's exaggeration of his initial impressions of Jill and the increasingly positive memories illustrate the psychological phenomenon known as rosy retrospection, where people's recollection of past events becomes more positive over time.
Step-by-step explanation:
The passage you provided illustrates a psychological phenomenon known as rosy retrospection or the tendency to remember past events as being more positive than they were at the time they occurred. This biased recall happens because over time, Derrick's feelings for Jill intensified, leading him to exaggerate his initial impression of her. It's a common cognitive bias where memories of events become more positive as time passes. For example, Dexter's view of Judy becomes more favorable and romanticized as he recalls their moments together, showing how the intensity of his emotions can alter his memory. This is evident as he even refers to moments of anguish in the relationship with a sense of fond nostalgia.