Everything that went wrong did so because of Jesse:
- Crazy 8 and his cousin were Jesse's connections
- Hank found Tuco because Jesse's car was lo-jacked and traced it out into the boonies. That led to the twins coming to ABQ and attempting their assassination attempt, which led to Hank being shot, which led Hank to Gale Boetticher's journal.
- Jesse went to kill the two dealers who killed the kid and Combo, even after specifically being told NOT to. This led to Walt's interference which completely destroyed his relationship with Gus that was on its way to healing.
- Jesse got Jane hooked on the heroin again, which got her to tell Walt how she was going to bring him down...which led to her death.
Jesse has always been the biggest pussy on this show. He killed one guy. He constantly got his ass kicked. He ended up being a huge rat. But I still love him.