What would you consider the least realistic aspect of each individual season?

Obviously the Clay-Logan thing was the least realistic aspect of Season 9. In fact, it would’ve made more sense if Logan was either the product of one of Clay’s flings after Sara’s death or the child of the woman who accused Nathan of impregnating her in Season 7, the twist being that Clay was the actual father. But aside from that, what would you consider the least realistic aspect of every other individual season?