good lock is how black people from detroit michigan say thank you because they don't want to look soft or weak in spartan nation and soldier city. or gangster city, or the black crime city. they also don't say thank you, or hi, or bless you or anything that makes them look weak to one person except one guy who don't care because he know he's strong and good.
good luck my nigga. nigga is a word african american call each other. good looking. my nigga means like my friend. but they don't let other races say it , to them its racist.