5. How Did Walt Poison Lydia?
Lydia finally got her just deserts in the finale and, at long last, that fabled ricin made its appearance after much reference throughout the last two seasons. After secreting it behind a light switch at his home, Walt retrieved the deadly vial of poison and put it in Lydia's precious Stevia sweetener at the coffeehouse. The sinister ex-chemistry teacher was lurking in wait of Lydia as she walked in for a cup of jo, and had placed the Stevia sweetener at an empty table that she just so happened to have chosen to sit at. But how did Walt know she was going to sit there? In previous episodes, Lydia was shown to have been sitting at a booth rather than the rounded table where she ultimately met her end. Put it down to poetic licence, or a plot hole, if you will, but it's still baffling as to how Walt knew where to stash the ricin.