Myself I have been involved with weed a long time and never seen cocaine though my son did go into town one night and lock himself out of his car and have an experience we call "the night of the living baseheads."
The best drug dealer at my old school was a guy who would take chances nobody else would; I knew him somebody who dealt weed, psychedelic mushrooms and acid to my friends although I was persona-non-gratis with him because he was seriously criminally minded and led a gay bashing gang that mostly bashed straight people who were perceived as allies [1], although it took just one snarky comment (my case) or advising somebody being shot at with a paint pellet gun to see the police (the popular president of the paint pellet gun club.)
He eventually got caught bashing in an RA in the face with a rock shot with one of those rubber band catapults people use to shoot water balloons at the beach. He was banned from campus but I saw him once when he was dropping off a delivery for a friend. My friend later told me that he'd been caught on videotape dealing 3kg of cocaine to an undercover cop and he did time.
That's an unusual case. Except for that guy and the Vietnamese kid who took money and never delivered the weed to my wife when she was in high school, all the pot dealers I knew were basically responsible and law-abiding people who only dealt pot and other soft drugs. Funny somebody dropped a dime on the later.
[1] this was the 1980s during peak AIDS panic and I guess they were afraid if they spilled gay blood they might get AIDS or something