Angst? What Angst?: The family doesn't seem very concerned that Daphne had her memory wiped by Katie's boyfriend suffered psychological trauma that made her lose her memory...
Of course, when Jim finds out later how it really happened...let's just say it's a good thing Katie can serve as a universal Morality Pet.
Fridge Brilliance: Why did Watcher fall for Katie? Well sure, she's cute, smart, and all these things. But remember else what both of them have in common. They wanted to be accepted (more or less). Watcher wants to be normal and have a family/be loved. Katie was a social awkward virgin looking for love as well. He sees in her as sort of fellow outcast.
Then in the season one finale, they take the elevator when they know they bad guys know where they are and are actively watching.
In the introduction for the shapeshifter character, why didn't Jim just ask "Steph" to use her super speed?
When Watcher terrorizes Daphne before wiping her memory of the past three months and all of the experiences and bonding the family has had in that time. It's very reminiscent of a rape scene, which is fitting
In the same episode, Watcher telekinetically forces Dr. Chiles to commit suicide. Made even worse by Daphne's vision of Watcher's memory of the attack.
They Wasted a Perfectly Good Plot: Other than hiding the Watcher's secret, Daphne's memory loss has no impact on the story, immediately being caught up to speed by absorbing the memories of the others.
But that not only conveniently covers the memories of the Watcher's secret, it also sets a precedent for future uses of this plot which will help avoid having it feel like an ass-pull.
Yay: There's Les Yay between Katie and Stephanie. There's Ho Yay between George and Jim. There's Foe Yay between Stephanie and Dr. King. Lotta yay going around. Given all the Yay going around, one could be forgiven for not realizing that Stephanie and Jim are married with children without the scenes where they're in their bedroom or what have you.
The Victoria!Joshua/Katie kiss in the Season One finale, if you think about it.