9. He Injected Wendy
In the fallout of the shoot out between the Sons, the Galindo Cartel, and the Irish, Wendy was taken as a hostage by Galen to be traded back for the money Romeo stole. Nero ultimately lent the club the money to get her back, but not before she learned about Abel's past.
When she was with Galen she found out that her son had been kidnapped and taken to Belfast several years earlier. Wendy was already looking to get back into Abel's life, and this gave her the ammunition and leverage to report Jax and Tara.
Wendy threatened as much to her ex-husband and his new wife, and she was repaid with violence. Jax burst into her home and told her he would call the rehab centre where she worked and tell them she showed up stoned at Abel's day care, babbling about him being kidnapped by the IRA.
To back this up, he slammed a needle into her arm without a care for the months and years she worked to become clean and sober. This was a complete abuse of the addiction Wendy had worked so hard to leave behind, and while she was only trying to get Abel to safety, instead Jax could have ruined her life.