The Wire showed us that selling drugs can be a very complicated business, and that those who do it successfully operate with a very high degree of professionalism. Even at the street level, there are processes and procedures related to money handling and drug hand-offs that have to be strictly adhered to to limit exposure to rivals and police surveillance.
An example of one of those procedures: Don’t call someone on the phone and offer to sell them drugs. That’s called a narco no-no. And if you forget that because of some catastrophic head injury you’ve recently suffered, at least remember that if you call someone to sell them drugs and the person replies that you got the wrong number, do not offer to sell that person drugs.