In both cases what happens is Katrina is genuinely, in her way, Trying To Be Helpful. She assumes that her experience with horror pictures can be beneficial to you. (Mistakenly believing that, like her, you actually want to grow to like them.) And she assumes her experience with eye surgery can be beneficial to Sarah. (The latter situation is seasoned somewhat by the additonal quirk that, given the chance, she will yack about her and other people's medical problems until the audience starts to scream and thrash about.) She means entirely well. It's just that she's trying so hard to Be Helpful that she goes at it like a dachsund trying to dig a rat outta the ground.

Anyway. Luckily her myriad issues are merely a subject of minor academic interest in my life, now that she's no longer running up my water bill.