So many people grew up with challenges, as I did. There weren't always happy things happening to me or around me. But when you look at the core of goodness within yourself - at the optimism and hope - you realize it comes from the environment you grew up in.

This quote is saying that many people, including the speaker, experienced difficulties while growing up. This could include difficult living situations or bad situations in their home life. Despite these obstacles, the speaker is still optimistic and hopeful because they recognize that these difficult environments can be the source of their internal strength. This suggests that even if a person’s environment is challenging, they have the power to find and cultivate the positive aspects of their upbringing and use them to build a better future.