Final answer:
Greg's lousy summer may have been caused by experiences similar to those faced by Andy, Dexter, and Kim in the given passages, such as homesickness, unrequited love, or academic issues.
Step-by-step explanation:
One reason Greg's summer was pretty lousy was attributed to the negative experiences he encountered. From the texts provided, various characters such as Andy, Dexter, and Kim faced challenges that could parallel Greg's lousy summer. Andy initially displayed bad behavior due to homesickness, Dexter was emotionally affected by Judy Jones's indifference, and Kim blamed external factors for his failure in history.
Although Greg's precise situation isn't detailed in the excerpts, it can be inferred from these narratives that challenges like homesickness, unrequited love, or academic failures can contribute to an unpleasant summer experience. For Andy, overcoming homesickness and embracing the music camp turned his summer around, suggesting that facing one's difficulties can lead to personal growth and a more rewarding experience.