While I'm in the addictive mode and continually watch the series, I do it because it's exiting and I just love mysteries. But afterwards, I love thinking about each cases and engaging my brains on major things such as who Bourbon and Scar Akai is and other major things like that.
I also like how Conan has to deal with being the cruel bringer of justice. At the end of the Gomera case, while he was expected to be thanked, he was told that not everything is black and white. Most people, not just the murderers, of the series would say the same thing. Conan is never allowed to side with the criminal but sometimes he can't help but feeling sorry for the criminals which can be hard. Even Sherlock Holmes let a murderer get away once and concealed the truth about her identity. Conan, being a Sherlock fan and through experience, would understand how he felt. He realizes that the world is not black and white but at the same time, he is fighting something that is completely black: The BO. This organization causes the blackness of one's heart to be in the dark society. As Gin said, "Mixing black with black will only get you black." However, there is "white" as well. Ran's pure heart for all people lets Conan see good in people as well because as she represents, there's good in everyone. Some people see this as weakness but in reality, this makes them strong (which metaphoracally explains Ran's karate). Perhaps this is why Conan tries to make the criminals realize that what they were dong were wrong: while they'll never be cleansed of the blood they spilt, they can still redeem themselves. Ai is the exemplary. She has turned her back on the society of pure evil and has found her way to those will help her redeem herself. Although at first she was uncomfortable to accept Ran, she eventually accepts her and has time and time again redeemed herself. She has gone from a person willing to test drugs on live human beings, to a kind person willing to sacrifice herself for the safety of others. The thing she wants to protect them from is the pure blackness that may mean she doesn't want them to fall victims to society.