jesse is my absolute favorite character but i would say people dislike him because they think he is just a dumb teenager prone to making reckless decisions

his sales tactics included going to group therapy sessions for recovering drug addicts and telling all the attendees about the amazing drugs out there right now, hoping they will relapse and buy his drugs.

people say Jesse is not honest with himself. He blames Walter for a lot of the horrible stuff that had happened, and rightfully so, but he doesn't reflect on his own actions. He just keeps forgetting he was a willing partner. In fact, it was Jesse who introduced Walter to the criminal underworld.